desktop won't change in XP

running XP home, SP1
I've recently had a bunch of virus probs, but those all seem to be cleared up now....
Only thing still screwed up is my desktop. It stays white and the brightness seems to flash intermitantly.
Themes seem to be installed OK, and in the services menu, they show as running with no problems.
I can go to control panel and change to a different desktop, it will preview OK, but then the desktop still is just white. I have noticed when I boot up the desktop pic is displayed correctly for just a second, then when the icons come up it goes to white.
When I right click on the desktop and select properties there is only a general tab... I thought it should also have more tabs for me to adjust the appearance.
Did I delete something important while I was removing my viruses?
Your help is appreciated as seeing my puppy's pic on my computer makes me smile.

chickie

 

Did you try system restore?

 

No, I currently have system restore turned off.