Folders won't Close!

Well, something has happened and I have no idea what. Without
installing any software or changing any configs I find out that I can
not close any folder after opening it. I can't close by the upper
right hand "X" or close them by right clicking the folder in the
toolbar and clicking on "Close". The only way I can close a folder is
to bring up the Ctrl-Alt-Del menu and choose "End Task" on the listed
open folder(s).

I have run AdAware, SpyBot S&D, Pest Patrol, Spy Sweeper and have run
a full system scan with Norton and find Nothing.

Any Ideas?

Regards,
TR