Occasional crashes playing divx/xvid

Sometimes (well, quite often actually) my pc crashes while watching a dixv or xvid movie through the tv-out. Sound becomes an electronic shriek and the picture look like this:



The pc only responds to the reset button and upon returning to the windows desktop, it has readjusted the screen size to 800x600 (I usually run 1024x768) on that machine).

If I then reload BSPlayer, I can find the position in the movie where it crashed and usually watch the rest without further problems.

I have no idea what causes this, and I'd really like to get some pointers as to where to look.

I'd be happy to supply specific system information if required.

Thank you

Thomas