small icons

for some reason most of the small icons on my computer
wont display properly. I can change them to large icons
and they look fine. They even function as they should,
they just don't look right. It's in folders and in the
taskbar. I have even found that in my favorites, the
internet explorer icon is messed up, but not all of them.
I have already checked for viruses and nothing turns up.
It's more annoying than anything. Please help. I'm down to
my last few hairs to pull out.