Delete VLC's preferences and cache files (type "%appdata%" into the Windows Explorer address bar and then delete the "vlc" folder).
If that does nothing try a different video output module:
http://wiki.videolan.org/WindowsFAQ#Why ... _output.3F
BTW you should be able to get access to other windows by pressing Alt+Tab, or do a Ctrl+Alt+Del to bring up Task Manager and close vlc.exe if it's non-responsive (shouldn't need to wait for a video to finish).
Arite.