weird thumbs action in folder view

Thumbnails take a long time (up to 1 min.) to display in folder view
and act erraticaly. Please see the image at
http://www.touart.com/images/weirdthumbs2.jpg

I have reformatted and reinstalled Win XP. I have changed video cards
from Nvidia to ATI Radeon and I have tried different monitors.

Any input appreciated, thanks

Rich
http://www.touart.com