I have an Associate of Applied Science degree in PC Support & Administration.
If you need to know the basics about optimizing your Windows XP computer, I highly recommend The Optimize Guides. They have even more links to programs than my Useful Freeware page, and tons of information too! I had wanted to make a site like theirs, but then I discovered them, so I don't have to - I can just link you there!
Yes, Firefox has flaws of its own. Read about why I'm still using it over IE 7.