Optimizing your computer
All Versions of Windows
Here are some basic steps to take to speed up your computer:
1.	Clean off your desktop! Every item on your desktop slows down your computer, so the fewer, the better...
o	Move all files into the "My Documents" Folder
o	Delete unused, unimportant links and files
o	Empty the Trash Can regularly
2.	Disable 'Active Desktop'! Though this disables the display of some backgrounds, it is terrible for your computer's performance, and is often the cause of crashes and hangs. Right click on the screen and hover over "View Web Content" and select the disable option
3.	Clean up your Start Menu! These links can also slow down your computer, if you can, get rid of empty folders, move programs into common folders, get rid of links to 'readme' and 'uninstall' and such
4.	Uninstall unused programs! In the Start Menu, there's a link to the Control Panel under Settings. In the Control Panel, you can Add and Remove Programs -- use this to find and uninstall programs that aren't used, or shouldn't be there. There's a tab that has Windows Components, from where you can delete Solitare and other Windows games, and get rid of things like the AOL/MSN Internet access files which are only useful in the USA
5.	Empty out your task bar! That area beside where the date and time are displayed is called the task bar. If there are a lot of icons there, they are probably effecting your computer's performance. Right-click on them, and you can exit or (preferably) exit and not load when Windows restarts. Common ones you don't need are MSN Messenger, AIM, and Y! Chat (only useful if you're online), RealPlayer (ditto), scanner detection, CD writing detection, and digital camera detection -- these are all accessible when you need them from the Start Menu, no need to constantly be bogging your computer down.
6.	Advanced users -- use msconfig! Select 'run' from the Start Menu and type msconfig and press Enter. This allows you to select more precisely what you want to load and not at Windows startup, but be careful! Don't disable anything you're not sure of.
7.	Clean up Internet Advertisements! Many programmes you download from the Internet come with 'ad-ware' which pops up advertising or tracks your usage patterns to sell them to advertisers. These all slow down your system. You can run Ad-Aware to clean them up. Note! This will disable any current KazAa installation you might have. If you wish to use KazAa, uninstall it using the Control Panel and install KazAa Lite, which has all the functionality with none of the ads!
8.	You should continue now by looking below at optimizations specific to your version of Windows, but, once you're done with that, at the end of everything you want to do to your computer for a few hours, you should
Optimize your Disk! Open up My Computer and right-click on your Hard Drive (C:) and select Properties. On the window that first appears, press the Disk Cleanup button first, and let it find ways to clean your disk. Note! Using Disk Compression is not recommended. After you finish that, click on the tab called Tools, and check the disk for errors. Once that is complete, you should defragment your disk -- this can result in much faster computer usage, safer CD burning (fewer errors!), and general better performance. Note! This can take several hours, depending on the size and speed of your drive, and it is important that nothing else uses the computer -- even programs. You may have to disable virus protection and any automatic/schedule programs while your disk is defragmented
Windows 95/98/ME
There is a tool which will clean up your computers 'logbook' of programs and files, which can result in massive performance increases. The same tool can also be used to search for extraneous or duplicate files. This tool is EZCleaner. Note! DO NOT USE THIS on Windows XP, 2000, or 2003!. The best tool in this program is the "Registry Cleaner" 
Windows XP
XP has a tool called RegScrubXP, which cleans the Registry of XP much like EZCleaner for 98.