Hard drive cleanup
Back in the days when I using Windows 95/98 before XP (I never used 2000 for personal use), I would routinely, repeat, routinely format the hard drive and reinstall the entire thing every two to three months. It was almost as if you had to. All my apps were copied to a CD so I'd just reinstall when I needed to.
Between three computers I have only had to reinstall Windows XP once, and that was for the file server because I wanted a completely "clean" install with no unnecessary crap in it. It didn't need it but I did it anyway.
I haven't had to reinstall XP on the laptop since I've owned it which is nothing short of awesome. The biggest advantage to XP over other versions of Windows is that it doesn't get slower over time. Long time users of Windows know what I'm talking about. For some strange unknown reason, your computer gets slower and slower... even if there is no spyware/malware/viruses/etc. Fortunately XP doesn't do that. It only gets slower is you have too much crap installed.
Part of the reason my XP runs so well is due to the fact I keep resident applications at a minimum. I do not have four instant messengers running all at once. I don't use software-based firewalls (that's what the router is for).
I also do not use any Microsoft-specific application (like Internet Explorer or Outlook Express) save for MS Office apps like Word and Excel.
For those interested in what my taskbar icons look like:
The biggest reason my XP runs fast (as it should) is because I keep the hard drive "clean". I noticed some performance issues, so I opened up Windows Explorer (no, not Internet Explorer, that's different) and did a search for *.*, then sorted by size with the largest files at the top of the list. What I suspected was true, I had many large files that did nothing but waste hard drive space. There were some Linux ISO images, video files and so on.. so I got rid of all them.
Then I clean out my temporary folder. This is a hidden folder in XP. The folder is located at:
C:\Documents and Settings\[XP user name]\Local Settings\Temp
I delete anything in there, reboot, then run Disk Defragmenter and reboot one more time.
Granted this is overkill, but I like my XP to run as best as it can. 😉