For instance, is your 'My Computer' icon displaying the 'default' icon instead of the usual 'My Computer' icon?
Or maybe some of your 'start menu' icons are showing the default icon instead of the proper
Well I had this problem recently and the cause resulted from switching between two different video cards. I was having various issues with the cards, you know - stupid driver issues (?)... well, there just so happens to be an "icon cache" that get's created by Windows XP. This cache somehow became corrupted. I do not know how, but here is how to fix it:
Delete the cache.
Swith your desktop color depth between settings - this should create a new cache.
Look at your icons. Are the displaying properly now?
...good.
Perhaps later I'll fill in some more details. But, I just wanted to jot this down...quickly. Lest I forget.
Google is your friend!