Vista - Display Problems

I recently had a virus attack my laptop, but have gotten rid of it. Since
then I have been unable to change the desktop background. I get into the
display options and background, but I cannot click on a picture. None of the
pictures will highlight nor can I scroll through them. The only thing I can
do is use a solid color and change the color. I have tried right clicking a
picture in a file and set as background, but it never changes. It will
however pop up when I first start up my laptop, but then disappears. How can
I fix this problem? I'm tired of looking at a plain blue background.