Vista - Poor performance when opening folders containing avi files

Hi,

When I open a folder containing many AVI files in windows explorer, it
becomes very slow and a grey progress bar appears in the address bar. I can
stop this slowness by clicking a red cross that appears at the end of the
address bar that cancels whatever it is that vista is doing but I dont want
to have to do this every time I open the folder.

I have set explorer to "Always show icons, never thumbnails" in case vista
was trying to generate thumbnails but the problem is as bad as ever.

Does anyone have any ideas how to fix this?

Achelon