With Windows XP, quite a number of unnecessary programs run in the background by default. If you look at your task manager (which you can bring up with control + alt + delete), you may notice there are well over 20, sometimes even over 30 services running automatically on startup. Obviously, this slows the computer down, and particularly so when you have little memory, which to XP is anything less than 256MB. If you have a few minutes, this guide will inform you as to what you can safely turn off, and what some of the services actually do. I will be ignoring anti-virus and other installed services, because those vary widely, but I will cover every one of XP's default services. To make an easy reference chart, I will make all necessary services in white, all manual in yellow, and all the services you should disable in red.
I have extensively tested all these settings, but it is impossible to predict every problem that can occur. Keep in mind, these services can be important for Windows to run. I am not responsible for any problems that result from using this guide, because every system is slightly different. Use at your own risk.
To get to services, go to control panel, administrative options, services. This applies to the entire article.
Part One Part Two
Alerter - This service is largely unnecessary - it is intended to send out administrative alerts, in pop-up window form, but everything it might want to alert you to is either not important or covered by something else. Go ahead and set it to disable, and stop the service, unless you know you need it for a particular application.
Application Layer Gateway - If your computer hosts an internet connection that it shares with other computers, you might want this on. If that is the case, though, you should buy a router anyway - you'll be surprised at how handy they are, both freeing up resources and making the connection process easier. For everyone else, this is not needed. Set it to manual and stop the service.
Application Management - This service has never done anything useful for me. Set to manual, and stop it. If it is needed, you can easily restart it.
ASP.NET State Service - This service is intended to manage Windows Server 2003, so unless you have that running, you should disable this process and stop it.
Automatic Updates - This service downloads and updates your computer with critical Windows updates. You should go to Windows Update to update regularly anyway, which has many more updates than the service will deal with. Unless you need auto-update for a particular reason, I recommend this be disabled and stopped.
Background Intelligent Transfer Service - This is designed for client-server communication between a PC and HTTP server. Unless you know what this means, chances are you don't need it. Set it to manual, and stop it. If you have connection or transfer problems, restart it.
ClipBook - When you copy and paste something, this service stores it in a ClipBook that allows other remote computers to access it. Disable and stop this service.
COM+ Event System - This is another of those notification services that virtually everybody can go without. Disable it and stop it.
COM+ System Application - This is related to the above service. Whatever you decide for COM+ Event System, do here as well.
Computer Browser - If you access a network drive, or are on a home network, you might need this, so set it to automatic. If your computer is standalone, though, disable it and stop it. It is only used for networked computers, so you won't need it.
Cryptographic Services - This checks the authenticity of files you want to install on your system. If you turn it off, you will probably get frequent messages when you install programs, and you won't be able to install updates from Windows Update. Leave it on automatic.
DHCP - If you have a static IP address, you can turn this off (disable). If you have a dynamic IP, use PPPoE, or dialup to connect to the internet, you will need this.
Distributed Link Tracking Client - This tracks source changes and updates your computer so it can locate a directory or file that has changed location. If you are on a corporate network, leave it on auto, otherwise disable it. If links to other files on your network break, then restart it.
Distributed Transaction Coordinator - Another tool designed for network administrators or database users who need files from several different places simultaneously. You probably won't need this service, so disable and stop it.
DNS Client - If you are on a network that automatically gives you a domain name, you need this on automatic. Home networks shouldn't need this, but many corporate or university networks will. If you are on a home network or a standalone computer, you can safely disable it.
Error Reporting Service - This is the program that gives you pop-ups after a program crashes. I recommend you disable it, and never look back. Microsoft doesn't really need individual error messages from every crash, and it saves you the hassle.
Event Log - This cannot be stopped, nor would you want to. It provides error logging, but not reporting, that is necessary for troubleshooting problems.
Fast User Switching Compatibility - If you want to share a computer with separate accounts for each user, this is a quick way to do it. However, it is better to log off or just share one account, because this combines memory and processor usage from each user, resulting in much slower computing. Set it to disabled unless you have a particular need for frequent user changes.
Help and Support - This disables the help and support icon on your start menu. Unless you use this regularly, disable it.
HID Input Service - This is designed to allow a user to program hotkeys or shortcuts using a combination of keystrokes or the mouse buttons. Almost all of them work without this service, though, so you might as well disable it. This is not one of the times when redundancy is a good thing.
IMAPI CD-Burning - This service, if disabled, says it will not allow the system to burn CDs. It only is a problem if you use Windows built-in CD burning, and if you do, you should buy Nero, Roxio, or something like it, as you will have many more options. You can definitely disable it.
Indexing Service - This is one of those bloated services that can be a major drag on your system. It is supposed to speed up searches by indexing files, but unless you want a constantly thrashing hard drive, you should disable it. It is not worth the amazing amount of resources it can consume.
Internet Connection Firewall/Internet Connection Sharing - If you share an internet connection over a network, or use Windows built in firewall service, leave it on. Otherwise, feel free to disable it.
IPSEC Services - This is designed to make your computer more secure, but few people need it. Disable it.
IPv6 Internet Connection Firewall - After Windows XP service pack 2 comes out, with a more advanced firewall, you might want this on. For now, XP's default firewall is laughable, so don't bother. Disable it, and practice good internet and e-mail sense instead of wasting resources on this.
Logical Disk Manager - If you plan to add hard drives to your system, or to modify partitions from within Windows, then leave this on manual. Otherwise, disable it.
Logical Disk Manager Administrative Service - Whatever you chose for the above service, do here.
Messenger - This allows spam to be sent to your computer, even if you don't have a browser or instant messaging program open. Definitely, absolutely, disable it.
MS Software Shadow Copy Provider - This is used in conjunction with Volume Shadow Copy, which most people do not need. It is used to make frequent backups of selected files, which enables you to make quick restorations without too much trouble. It is easy enough to make backups on your own, though, which is easier for beginners and good practice for all. I would disable it.
Net Logon - If you are on a domain (and chances are good that you are, if you are on any network, leave this on manual. If yours is a standalone computer, then disable it.
NetMeeting Remote Desktop Sharing - Another security risk that is easy to prevent. Disable this unless you want give hackers an easier time at your system. There is a security patch for it on WindowsUpdate, but if you disable the service, you don't have to worry about it.
Network Connections - This does exactly what the blurb tells you. Assuming you have a network card, this is best on automatic. If you are one of the very few who do not yet have a network card, leave it, and go out and buy one.
Network DDE - Used for certain applications to communicate between your PC and a server. Hardly anyone needs this, so disable it unless you have problems.
Network DDE DSDM - Same as above, as the two are inextricably linked. Kill it.
Network Location Awareness - Again, unless yours is a standalone computer, this is good to have. Leave it on automatic if you use Internet Connection Sharing, otherwise manual is best.
NT LM Security Support Provider - If you host a telnet server, leave this on auto. Otherwise, for everyone else, disable it.
[Nvidia Display Driver Service] - Not a native service to Windows XP, but common enough to mention. This can be disabled; in fact, I'm not sure it does anything!]
Performance Logs and Alerts - Collects data on a given schedule, and writes it to a log. If I want data about performance, I use the real-time Performance tool, in the administrative tool section of the control panel. This should be disabled.
Plug and Play - Plug and Play is one of the heavyweights, an essential service. Your PC's reliability will go to hell if you mess with it, so leave it on auto.
Portable Media Serial Number - If you use an iPod or mp3 player, you might want this. I have never needed it, so I recommend you disable it unless it causes problems with your player.
Print Spooler - If you have a printer, this is definitely a good thing. Only if you don't plan to use a printer should you disable it.
Protected Storage - This is needed if you use Internet Explorer's autocomplete function or password saving. Otherwise, you can disable it. I personally like autocomplete, since I don't use Favorites, so I recommend you leave it on auto.
QoS RSVP - This can bottleneck your network traffic, and doesn't do anything useful for most people. I recommend disabling it, as the slowdown it can cause is largely unnecessary.
Remote Access Auto Connection Manager - When your computer requests to connect to an external IP, this service is needed. Leave it set to manual for the best of both worlds. It should start up if needed, but will not consume resources unless it is required.
Remote Access Connection Manager - Much like the above service, you should follow the same rule. Manual is the best option for everyone.
Remote Desktop Help Session Manager - If you want to have the ability for someone to help you with a computer problem from afar, this should be left on auto. Support can be done in other ways, though, so disable it unless you feel you really need it.
Remote Procedure Call - Another big one. Lots of services depend on this; it is absolutely necessary. Leave it on auto unless you want a headache.
Remote Procedure Call Locator - Despite the similarity to the above service, this one is unnecessary. Disable it, and gain a few more system resources.
Remote Registry - Letting someone remotely control your registry is a bad, bad idea. You are giving them permission to wreak havoc. Make sure you disable this one.
Removable Storage - Supposedly, you need this for any flash drives, external hard drives, etc. I have used both a flash memory drive, and a USB hard drive, without any problems even with it on manual, so I recommend that setting. If your removable drives have problems, then put it back on auto.
Routing and Remote Access - If you are connected to a corporate network, there is a chance you might need this. I recommend trying manual, and if problems occur putting it back on auto. For everyone else, it can safely be disabled.
Secondary Logon - If you want to use multiple user accounts at the same time, this allows it. For a single user, or shared account, this is unnecessary, so I recommend it be disabled for those people.
Security Accounts Manager - Ironically, this "security service" is a security risk, and should be disabled.
Server - If you share files, internet connections, or printers across a network, you should leave this on auto. For all others, disable it. I recommend automatic, just to be on the safe side.
Shell Hardware Detection - This is used to autoplay, so for most it would be wise to leave it on. If you don't add removeable devices or autoplay, you should be able to kill it, but be ready to restart it if there are problems.
Smart Card - If you have a smart card reader, you probably need this. If you don't know what a smart card is, disable it unless you have problems.
Smart Card Helper - Same as above.
SSDP Discovery Service - Yet another one. Microsoft says this is a security risk, so turn it off to make your computer more secure.
System Event Notification - I have never used this, and my computer runs just fine. Disable it.
System Restore - You should make regular backups, and if you do, this is largely useless. Disable it by right-clicking My Computer, System Restore tab.
Task Scheduler - I fought this service for a while, but it kept coming back. Too many other things depend on it to mess with it, so leave it on automatic and know it is helping you out in the background.
TCP/IP NetBIOS Helper - TCP/IP should be used, not NetBIOS, so disable this unless you know you need it.
Telephony - If you have a dialup connection, or DSL with PPPoE, leave this on auto. For LAN, cable, of if you use a router, this should be disabled.
Telnet - Unless you know what telnet is, leave this off. The average user does not require it.
Terminal ServicesIf you use any of the services listed under the description of this service, then leave it on. I don't, so I recommend it be disabled.
Themes - If you want to be able to easily change the appearance of your computer's interface, or run a program like WindowBlinds or Style XP, you need this. Since this covers most people (I think, anyway), I recommend it be left on auto.
Uninterruptable Power Supply - I have a UPS, and still it is unnecessary. I don't need to monitor it constantly, so why bother? I vote for disable, as it will rarely be useful for most people.
Universal Plug and Play Device Host - This is similar to SSDP Discovery, and equally bad. Disable it to improve security.
Upload Manager - Needed for Internet Connection Sharing, should be disabled for anyone who isn't using that.
Volume Shadow Copy - See MS Software Shadow Copy Provider earlier in this guide. Average user should disable it.
Webclient - Not sure if this one has a purpose, but it doesn't mind being disabled, so I recommend you do the same.
Windows Audio - Windows Audio is another important one. If you ever use any type of audio listening/recording/playing device, then leave this on auto.
Windows Image Acquisition - If you have a camera, it might be better on manual. You could try without, as it might well work, and unless you use a camera you should disable it.
Windows Installer - Used for certain installation file types, manual is the best setting to ensure a reliable platform.
Windows Management Instrumentation - Very important, leave this on auto.
Windows Management Instrumentation Driver Extensions - Some say this is necessary, as the above service. However, I have mine set to manual and have no problems.
Windows Time - Used to synchronize your system clock with time.windows.com, which I feel is useless. My clock is plenty accurate, and easy to adjust if it does deviate a little. Disable it, and have one less thing to take your precious resources.
Wireless Zero Configuration - If you use wireless devices (excluding wireless mice/keyboards, which do not need this), leave this on. Otherwise, leave it on manual.
WMI Performance Adapter - I have never needed this, so chances are you won't either. If you have problems after you disable it, then try setting it to manual.
Workstation - The last, and not least. Leave this one on auto so you don't have to worry.
So there you have it, boys and girls. Although some say all this was unnecessary, I highly disagree. In real world experiments, these tweaks have lowered memory usage on startup of Windows from almost 200MB to well under 100, especially important for slower or less well endowed systems. Definitely worth doing every time you install Windows, whether or not everyone agrees. After all, you paid for your memory, so why not utilize as much of it as you can for what you want to do, rather than excess that Windows incorporates for people who don't know the difference. Also, as you have read, killing these extra services can substantially improve security. It doesn't matter if a service has a hole in it that hackers can exploit, if it isn't running in the first place. Just remember, these can affect your system, and it is good to back all your settings up before you tweak them. With that said, enjoy your newfound speed!