Some Windows Vista users have been getting an error stating "Windows host process (rundll32) has stopped working". If you have the Nero burning software installed, it could be this that is causing the problem.
Browse to the following directory using Windows Explorer:
C:\Program Files\Common Files\Ahead\DSFilter\
Then rename the following items (if they exist) from .ax to .old, as this will prevent them from being accessed:
This will prevent some of the Nero codecs from rendering video thumbnails, which is most likely the cause of the problem.