QUOTE (Shark007 @ Nov 17 2008, 07:44 AM)

On a clean istallation of Vista x64 the Disk Cleanup Utility points to the 32bit version by default.
Rightclick the Disk Cleanup Utility and choose properties;
In the Target box: change SYSWOW64 to SYSTEM32
run the utility again, reboot, browse to the folder with the video's, thumbnails should get newly created.
shark
this did not work either. I'm not sure what could be wrong.