All I have to work with is the Restore CD. Of course, that had stuff my mother doesn't need, such as CompuServe, AOL, Winamp, Real Player, Viewpoint Media Player, etc. I removed those things before updating Windows, including SP2, and then installed AVG, Spybot S & D, and CCleaner.
I did manually remove the files for BigFix and also removed a few Registry entries for BigFix. I also downloaded and ran Eusing Free Registry Cleaner. It removed additional entries for BigFix. Still, the Registry contains an entry which keeps reappearing in scans by Eusing Free Registry Cleaner. I've tried to manually remove that and it can not be removed.
I could start over and repeat the restore, then try removing BigFix before doing anything else. Guess I'll either do that or leave it as is.