Defragment your hard drive
It is a good idea to defragment your hard drive on a regular basis. Defragmenting puts all the files you use in order and consolidates all of your free disk space in a large block. Windows provides a ;Disk Defragmenter8; in system tools. You can find it by clicking on the start button and selecting, programs, accessories, system tools. You can also try opening ;My Computer8; right click on the drive you want to defragment, click properties, and select the tools tab. You can also run ;Scandisk8; in this manor. If you are having problems with scandisk or disk defragmenter not completing the task or having to restart a lot, try starting windows in safe mode and then run the program. To start in safe mode tap the F5 key after you start your computer but before the windows screen pops up. You will see a box that explains your running in safe mode. Click O.K. and proceed to run scandisk or defrag. When running in safe mode your video display will change to 16 color and you will not have sound. Do not be alarmed, everything should be back to normal when you restart your computer.

Upgrading software
In an ideal world, software updates would never cause problems. In reality, while some installation routines check for existing components, they don't always check to see which versions of those components are left on your PC, so newer programs may inadvertently use older versions of shared files, drivers, or DLLs and cause a variety of problems, depending on the file. In other cases, installation routines overwrite software modules that other programs share. For example, if winsock.dll (a vital file that allows Internet access) is overwritten, programs that use that file will be unable to reach the Internet. If you plan to upgrade a software package, back up your work files for that program, and uninstall the older version of the software first. Then install the new version from scratch and reinstall your work files.

Removing programs
Virtually every Windows program registers itself with the system, or creates a log in the Windows Uninstaller utility that records which files you have added to the system and lists any changes you've made to the system's configuration. Thanks to this painstaking process, when you uninstall the program using the Add/Remove Programs icon in your Control Panel (or the program's own uninstaller), Windows removes all traces of the program and its system alterations. If you decide you don't want a program anymore, don't just drag the program's folder to the Recycle Bin. Simply trashing a program may leave desktop icons, unnecessary drivers, or unlinked Registry entries on the system or may destroy shared files that other applications also use. Instead, to remove any program, click Start / Settings / Control Panel, then double-click the Add/Remove Programs icon. Select the Install/Uninstall tab, highlight the program you want to remove, and click the Add/Remove button.

Recycle Bin and Internet Explorer's Cache
By default, both the Recycle Bin and Internet Explorer's Cache want to consume ridiculous amounts of your hard drive space. Right click on the Recycle Bin, select Properties, and on the Global tab, decide how much space you want the Recycle Bin to consume, either for all drives in your system, or on a per-drive basis. (It's a percentage of the total space. I adjust the slider way to the left, so I'm using "only" a few hundred megs of space for rubbish.)