The following will help keep a Windows computer running smoothly for years to come and most cost you nothing:

• Have plenty of RAM – at least 1GB for XP and 2GB for Vista or Windows 7.
• Use the built-in Windows maintenance tools (e.g. Disk Cleanup, Disk Defragmenter, Disk Error-checking).
• Don’t let the drive where Windows is installed have less than 10% free space.  If it falls below that, it’s time to start uninstalling programs or moving data.
• If you use Internet Explorer, delete cookies and history on a regular basis. Configure Internet Explorer for 256MB of temporary files and also configure it to empty temporary files when the browser is closed.
• Make sure to stay current with Windows updates.
• Uninstall any software that is not used.  Do this properly through Add or Remove Programs.
• Don’t install any unnecessary hardware or software.
• Reboot the computer on a regular basis.
• Keep all vents clear of obstructions.  Check fans regularly to verify that they are functioning correctly and replace any that are not.
• Follow the tips under my Malware section.
• Stay away from any “registry cleaner” type programs.  All it takes is one incorrect registry “clean up” and your system could be damaged beyond repair.