Here is a list of unneeded Windows services that you can turn off to speed up your slow computer:
AdobeLM Service: Not all computers have this service, still it is useless. Just disable it if you have it running on your machine. (Some readers have pointed out that by disabling this service you may have startup and registration issues with Adobe software.)
Alerter: Disable this one if you are not on a network because you will not receive alerts.
Application Layer Gateway Service: Unless you want to share your Internet connection, turn this off as this service provides support for 3rd party protocol plug-ins for Internet Connection Sharing
Application Experience: Windows 7 users can safely disable this service and gain increased responsiveness at launch time.
Application Management: Set this to manual.
Automatic Updates: Disable it if you do not require auto-updating and patching of Windows. It is pretty useless if you use auto-patcher by NeoWin to update your Windows OS. Thus, you will save bandwidth.
Background Intelligent Transfer Service: Disable this if you do not need
Automatic Update as well. This is also a potential security threat as it uses idle network bandwidth to transfer data.
ClipBook: Disable this if you are not on a network, since you do not need to share anything.
Computer Browser: Disable this too if you are not on a network, as you do not need to browse and monitor connected computers.
Cryptographic Services: Set this to manual if you are not sure you need it.
Diagnostic Policy Service: Disable this safely you don't need to be alerted of incorrect software installations on your machine.
Distributed Link Tracking Client: Disable this service if you have only one computer on a network, or if you do not access other computers.
Distributed Transaction Service: Set this to manual.
Error Reporting Service: Disable this service for reporting errors to Microsoft, because they will hardly even reply to you for any error you get. This also saves a lot of bandwidth.
Event Log: Set this to automatic.
Fast User Switching Compatibility: Disable it if you have only a single user on your computer, or if you do not use fast user switching feature much. That is, if you completely log off and then allow other users to use your computer, then you do not need this. Note that this service is completely useless for low memory computers.
Fax Service: Disable this if you do not use your PC to send / receive fax.
FTP Publishing: Disable this if you do not use FTP.
Help and Support: Set it to manual or turn it off if you do not use the help feature often. You can turn it on again at any time if you need help.
HTTP SSL: Set it to manual.
Human Interface Device Access: Turn it off if you do not use hot-keys or remote systems on your computer. Anyway if you use them sometimes, it is better turn it to manual.
IIS: The Internet Information Services provide the capabilities of a web server for your computer. If you don't need this option (you likely don't), turn it off safely.
IKE and AuthIP IPsec Keying Modules: If you don't need to use IKE or IPsec (most home users don't), disable this.
IMAPI CD-Burning COM Service: Set this to manual to save memory and time. Do not turn it off if you have a CD writer or a DVD writer attached to your computer.
Indexing Service: Turn it off, as this uses a lot of CPU. If you are an avid searcher, like a maniac, on your computer, leave it on since it will help you. If you know where your files are and do not use search that often, then disable it for your good.
InstallDriver Table Manager: Disable it safely.
Integrated Peripherals: Disable peripherals you do not need like network cards, integrated graphic or sound, etc. Go to "Run" and type "devgmt.msc" (without quotes)
IP Helper: If you don't need support for IPv6, safely disable this.
IPSEC Services: Set this to manual.
Logical Disk Manager: If you do not plan to add extra hard drives or modify the hard drive partitions on your machine, you can disable this. Otherwise, set it to manual.
Messenger: This service is not related with Windows Live Messenger. If you don't want unauthorized access to your PC, disable it.
Messenger Sharing Folders USN Journal Reader Service: If you do not use Live Messenger 8.0 (or higher) and / or you don't need sharing folders, you can safely disable this.
MS Software Shadow Copy Provider: Set this to manual.
Net Logon: Disable this if you are not on a network.
NetMeeting Remote Desktop Sharing: Disable this if you do not use the Remote Desktop feature.
Network Access Protection Agent: Safely disable this service if you are not using more than one computer and you do not need to manage a network.
Network DDE: Safely disable this.
Network Location Awareness: Safely disable this if you are not under a LAN or if you do not need to share files or hardware connected to your computer (like a printer).
Network List Service: You can safely disable this service if you are not on a network.
Network Provisioning Service: Disable this, as it is useless if you are not on a network.
Network Throttling: Select FFFFFFF to forbid Windows to send packages when accessing web streaming content.
NT LM Security Support Provider: Disable this, it is useless too.
NVIDIA Display Driver Service: If you do not use the features of NVIDIA Desktop, this service must be disabled; it is a big hog of memory.
Office Source Engine: Disable it if you have a MS Office CD handy always, its helpful if your installation goes corrupt.
Offline Files: Disable this if you don't use offline files.
Portable Media Serial Number Service: Set it to manual if you connect portable media to your computer, otherwise disable it.
Program Compatibility Assistant: If you don't need to run software designed for previous versions of Windows, you can safely disable this service.
Print Spooler: Disable it if you do not have a printer connected to your computer.
Protected Storage: Disable it if you do not allow strangers to sit on your encrypted storage computer.
QoS RSVP: Unless you're using QoS-aware programs and control applets, you can safely disable this service.
Readyboost: If you're not using this feature on Windows Vista (uses free space on USB drives to speed up your computer), disable this service.
Remote Access Connection: Disable this if you are not using any dial-up or VPN.
Remote Desktop Help Session Manager: Disable it if you do not use the Remote Desktop feature for help and support from Microsoft.
Remote Procedure Call (RPC) Locator: Set it to manual.
Remote Registry: Serious security threat if turned on, disable it no matter what.
Removable Storage: Disable it if you do not use removable storage drives, else turn it to manual.
Routing and Remote Access: Set it to manual.
Secondary Logon: Useless feature for most, disable it or turn it manual.
Security Accounts Manager: Disable it as it is pretty useless unless you use NTFS Encryption.
Security Center: Damn useless and irritating feature. Disable it.
Server: Set it to manual or disable it if you are not on network.
Shell Hardware Detection: Disable this to avoid being asked by AutoPlay if you want to perform an action after a specific input (inserting a CD, connecting an USB peripheral, etc.)
Simple File Sharing: Disable this service to avoid sharing your files with anyone on the web (Windows XP Professional only).
Smart Card: Disable it if you do not use smart cards on your computer.
SSDP Discovery Service: Disable it of not on network or don’t have uPnP devices on home networks.
System Event Notification: If you don't need to track system events such as Windows logon, network, and power events (most users don't), disable it.
System Restore Service: To improve system performance and take the minor risk of not being able to make your computer work like it did yesterday, disable it.
Tablet PC Input Service: If you don't have a tablet PC pen, disable it.
Telnet: Set it to manual if you use this feature, otherwise disable it, especially if you are a home user.
Terminal Services: Since you are not using Remote Desktop, etc... disable it for good.
Themes: Themes might be cool, but if you are not into pimping your desktop, you can safely disable this.
TCP/IP NetBIOS Helper: Set it to manual if on network, otherwise disable it.
Uninterrupted Power Supply: Disable it if you don’t have a UPS attached to the serial port of your computer.
Universal Plug and Play Device Host: Set it to manual.
Upload Manager: If you are not in a local network sharing data (files and / or services), disable it.
User Privilege Service: Set it to manual.
Volume Shadow Copy: Disable it if you do not backup your computer using System Restore or Windows Backup.
Windows Audio: If you don't have sound capability, disable it.
Windows Error Reporting Service: Disable this and you will never again be prompted to send an error report to Microsoft when a program crashes.
Windows Firewall / Internet Connection Sharing (ICS): Disable this if you have another firewall such as Norton or Zone Alarm installed, otherwise let it remain ON for better security.
Windows Image Acquisition (WIA): If you do not connect / use a camera or scanner with your computer, disable this service, else set it to manual.
Windows Media Connect: Disable this if you do not use things such as an iPod, etc... for your Windows Media Player.
Windows Media Connect (WMC) Helper: Disable this if you disabled the one above or if you do not need help from Microsoft.
Windows Messenger: Disable this if you are not on a network, it uses too much memory and it is a hog. Also, this is likely to become a security threat.
Windows Themes: Safely disable this to enjoy increased computer performance and free up memory (RAM).
Windows Time: Disable if not on a synchronized network.
Wireless Zero Configuration: Disable if not on a wireless network.
WMI Performance Adapters: Disable it, useless service for basic usage.
Workstation: Disable if you are not on a network. Or simply, if you are a gamer, just shut this one
AdobeLM Service: Not all computers have this service, still it is useless. Just disable it if you have it running on your machine. (Some readers have pointed out that by disabling this service you may have startup and registration issues with Adobe software.)
Alerter: Disable this one if you are not on a network because you will not receive alerts.
Application Layer Gateway Service: Unless you want to share your Internet connection, turn this off as this service provides support for 3rd party protocol plug-ins for Internet Connection Sharing
Application Experience: Windows 7 users can safely disable this service and gain increased responsiveness at launch time.
Application Management: Set this to manual.
Automatic Updates: Disable it if you do not require auto-updating and patching of Windows. It is pretty useless if you use auto-patcher by NeoWin to update your Windows OS. Thus, you will save bandwidth.
Background Intelligent Transfer Service: Disable this if you do not need
Automatic Update as well. This is also a potential security threat as it uses idle network bandwidth to transfer data.
ClipBook: Disable this if you are not on a network, since you do not need to share anything.
Computer Browser: Disable this too if you are not on a network, as you do not need to browse and monitor connected computers.
Cryptographic Services: Set this to manual if you are not sure you need it.
Diagnostic Policy Service: Disable this safely you don't need to be alerted of incorrect software installations on your machine.
Distributed Link Tracking Client: Disable this service if you have only one computer on a network, or if you do not access other computers.
Distributed Transaction Service: Set this to manual.
Error Reporting Service: Disable this service for reporting errors to Microsoft, because they will hardly even reply to you for any error you get. This also saves a lot of bandwidth.
Event Log: Set this to automatic.
Fast User Switching Compatibility: Disable it if you have only a single user on your computer, or if you do not use fast user switching feature much. That is, if you completely log off and then allow other users to use your computer, then you do not need this. Note that this service is completely useless for low memory computers.
Fax Service: Disable this if you do not use your PC to send / receive fax.
FTP Publishing: Disable this if you do not use FTP.
Help and Support: Set it to manual or turn it off if you do not use the help feature often. You can turn it on again at any time if you need help.
HTTP SSL: Set it to manual.
Human Interface Device Access: Turn it off if you do not use hot-keys or remote systems on your computer. Anyway if you use them sometimes, it is better turn it to manual.
IIS: The Internet Information Services provide the capabilities of a web server for your computer. If you don't need this option (you likely don't), turn it off safely.
IKE and AuthIP IPsec Keying Modules: If you don't need to use IKE or IPsec (most home users don't), disable this.
IMAPI CD-Burning COM Service: Set this to manual to save memory and time. Do not turn it off if you have a CD writer or a DVD writer attached to your computer.
Indexing Service: Turn it off, as this uses a lot of CPU. If you are an avid searcher, like a maniac, on your computer, leave it on since it will help you. If you know where your files are and do not use search that often, then disable it for your good.
InstallDriver Table Manager: Disable it safely.
Integrated Peripherals: Disable peripherals you do not need like network cards, integrated graphic or sound, etc. Go to "Run" and type "devgmt.msc" (without quotes)
IP Helper: If you don't need support for IPv6, safely disable this.
IPSEC Services: Set this to manual.
Logical Disk Manager: If you do not plan to add extra hard drives or modify the hard drive partitions on your machine, you can disable this. Otherwise, set it to manual.
Messenger: This service is not related with Windows Live Messenger. If you don't want unauthorized access to your PC, disable it.
Messenger Sharing Folders USN Journal Reader Service: If you do not use Live Messenger 8.0 (or higher) and / or you don't need sharing folders, you can safely disable this.
MS Software Shadow Copy Provider: Set this to manual.
Net Logon: Disable this if you are not on a network.
NetMeeting Remote Desktop Sharing: Disable this if you do not use the Remote Desktop feature.
Network Access Protection Agent: Safely disable this service if you are not using more than one computer and you do not need to manage a network.
Network DDE: Safely disable this.
Network Location Awareness: Safely disable this if you are not under a LAN or if you do not need to share files or hardware connected to your computer (like a printer).
Network List Service: You can safely disable this service if you are not on a network.
Network Provisioning Service: Disable this, as it is useless if you are not on a network.
Network Throttling: Select FFFFFFF to forbid Windows to send packages when accessing web streaming content.
NT LM Security Support Provider: Disable this, it is useless too.
NVIDIA Display Driver Service: If you do not use the features of NVIDIA Desktop, this service must be disabled; it is a big hog of memory.
Office Source Engine: Disable it if you have a MS Office CD handy always, its helpful if your installation goes corrupt.
Offline Files: Disable this if you don't use offline files.
Portable Media Serial Number Service: Set it to manual if you connect portable media to your computer, otherwise disable it.
Program Compatibility Assistant: If you don't need to run software designed for previous versions of Windows, you can safely disable this service.
Print Spooler: Disable it if you do not have a printer connected to your computer.
Protected Storage: Disable it if you do not allow strangers to sit on your encrypted storage computer.
QoS RSVP: Unless you're using QoS-aware programs and control applets, you can safely disable this service.
Readyboost: If you're not using this feature on Windows Vista (uses free space on USB drives to speed up your computer), disable this service.
Remote Access Connection: Disable this if you are not using any dial-up or VPN.
Remote Desktop Help Session Manager: Disable it if you do not use the Remote Desktop feature for help and support from Microsoft.
Remote Procedure Call (RPC) Locator: Set it to manual.
Remote Registry: Serious security threat if turned on, disable it no matter what.
Removable Storage: Disable it if you do not use removable storage drives, else turn it to manual.
Routing and Remote Access: Set it to manual.
Secondary Logon: Useless feature for most, disable it or turn it manual.
Security Accounts Manager: Disable it as it is pretty useless unless you use NTFS Encryption.
Security Center: Damn useless and irritating feature. Disable it.
Server: Set it to manual or disable it if you are not on network.
Shell Hardware Detection: Disable this to avoid being asked by AutoPlay if you want to perform an action after a specific input (inserting a CD, connecting an USB peripheral, etc.)
Simple File Sharing: Disable this service to avoid sharing your files with anyone on the web (Windows XP Professional only).
Smart Card: Disable it if you do not use smart cards on your computer.
SSDP Discovery Service: Disable it of not on network or don’t have uPnP devices on home networks.
System Event Notification: If you don't need to track system events such as Windows logon, network, and power events (most users don't), disable it.
System Restore Service: To improve system performance and take the minor risk of not being able to make your computer work like it did yesterday, disable it.
Tablet PC Input Service: If you don't have a tablet PC pen, disable it.
Telnet: Set it to manual if you use this feature, otherwise disable it, especially if you are a home user.
Terminal Services: Since you are not using Remote Desktop, etc... disable it for good.
Themes: Themes might be cool, but if you are not into pimping your desktop, you can safely disable this.
TCP/IP NetBIOS Helper: Set it to manual if on network, otherwise disable it.
Uninterrupted Power Supply: Disable it if you don’t have a UPS attached to the serial port of your computer.
Universal Plug and Play Device Host: Set it to manual.
Upload Manager: If you are not in a local network sharing data (files and / or services), disable it.
User Privilege Service: Set it to manual.
Volume Shadow Copy: Disable it if you do not backup your computer using System Restore or Windows Backup.
Windows Audio: If you don't have sound capability, disable it.
Windows Error Reporting Service: Disable this and you will never again be prompted to send an error report to Microsoft when a program crashes.
Windows Firewall / Internet Connection Sharing (ICS): Disable this if you have another firewall such as Norton or Zone Alarm installed, otherwise let it remain ON for better security.
Windows Image Acquisition (WIA): If you do not connect / use a camera or scanner with your computer, disable this service, else set it to manual.
Windows Media Connect: Disable this if you do not use things such as an iPod, etc... for your Windows Media Player.
Windows Media Connect (WMC) Helper: Disable this if you disabled the one above or if you do not need help from Microsoft.
Windows Messenger: Disable this if you are not on a network, it uses too much memory and it is a hog. Also, this is likely to become a security threat.
Windows Themes: Safely disable this to enjoy increased computer performance and free up memory (RAM).
Windows Time: Disable if not on a synchronized network.
Wireless Zero Configuration: Disable if not on a wireless network.
WMI Performance Adapters: Disable it, useless service for basic usage.
Workstation: Disable if you are not on a network. Or simply, if you are a gamer, just shut this one