*Grin* I would love to delete 'Windows' as well. . . .
You could try to force empty the trash (if you haven't already tried)
"If an item in the Trash is locked, press the Option and Shift keys when you choose Empty Trash to delete it." (apple help)
I'm not sure if it will work on 'hidden' files, but it is worth a try.
Edit: Are you running Virtual PC by the way?