XP suddenly changed prefs on one user & won't change back

[Ameritrash73]

I have XP and this problem exists on only one user. The others are normal. The wallpaper is the standard blue and when I select any other wallpaper, nothing happens. Text and icon size and other prefs have been altered and also cannot be changed. Also I am unable to download anything as that user and everything drags. I have run Norton Anti-virus and Win-doctor, Adaware, and Spybot, but only on other user log-ins because under the affected log-in, these programs just freeze up if I try to run them. It seems really odd to me that the problems are so isolated to the one user. The only changes that I can think of that happened before the problem were some worthless Windows updates, but they were performed under a different log-in so that seems unlikely to be the culprit but considering all of the Windows update problems I've heard about, nothing would suprise me.

Here are my specs:

Windpws XP sp2
NVIDIA GeForce FX5700 LE
Athelon 2800XP
1.5 gig mem