An "animated GIF" has messed up my desktop!

I recently tried to use a small animated .GIF file as
a "tiled" background on my ThinkPad T20 running Windows XP
Pro.

ALL Microsoft and IBM patches and updates are current,
including the S3 Savage video driver. A full Noorton AV
scan of my system revealed zero viruses.

Since trying this .GIF tiling, my screen is now half black
on the left (the color I typically use for a background),
and the other is a blanched out white (I can see all of my
desktop icons on both sides of the screen). No matter
what background I choose (animated or not), the problem
still exists.

I can't reset things back to before, no matter how hard I
try. Has anyone ever experienced anything like this?

Thanks,
Sam
Sam