WinXP-Add/Remove is completely blank!

WinXP Home SP2 on a Dell laptop. I'm working on this for someone else, and I'm basically just doing a tune up; malware scans revealed almost nothing, but I think there may have been something in there in the past that caused some damage. Obvious signs of this were: task manager was disabled; control panel had been disabled; right clicking on the desktop for display properties had been locked out with a permission block. Naturally, I fixed these problems (it took less than 30 seconds of reg-edits). But Add/Remove Programs is totally empty... it's not just taking a long time to populate (I left it alone for 20 minutes) and it's not a big blank space. It is just empty. A screen shot is attached, but that isn't even really needed.
Any ideas?
I have done a bit of Googling, and the general advice is to do a system restore (I can't; no restore points) or a safe reload of XP. Reloading XP isn't a big deal, but I should be able to fix this without reloading, and I have a feeling that reloading wouldn't fix it anyway. I've already tried Dial-A-Fix and various DLL registrations....

Thanks

EDIT- problem solved, never mind!

 

How did you solve it?

 

I copied a clean appwiz.cpl from a known healthy PC to %system32%. I guess it had been corrupted on the laptop....

 

Thanks, I'll try to remember that fix. I have never seen a problem like that before.

 

Quite interesting! I suffered this problem in the past and I did nothing to solve it (it was not my pc)

Thank you I will remember this.

 

The MSKB contains an article for this; http://support.microsoft.com/kb/266668. However, dlb's solution seems much shorter/quicker. ;>)