Sudden GIF Strangeness

Hi,

I noticed since last night that for some reason I can't touch gif's in explorer without it freezing (the continuous "I'm doing something" cursor) and that's any kind of explorer, either in an open file dialogue box (Photoshop) or in explorer itself. I'm thinking that it may have something to do with the preview. In photoshop it gives you thumbnail of the file you're opening and in explorer it gives a thumbnail on the side. I notice it's while it's trying to display the thumb that it hangs.

JPG's and every other file I've tried seem to be fine. Any idea's??

I can't figure it out at all.

System is:
Win2k Pro sp 3
PIII 800
256Mb

Any help on this would be greatly appreciated. Thanks in advance....