Screen goes black when I try to double click??

[finkle]

this is odd... just started doing it... when I double click anything, my screen goes black and whatever I DC on won't open, if I RC and use open, everything is fine...waits a couple seconds then my desktop comes back like nothing happend...

Windows XP Pro w/sp2
Hardware below in sig...
the OC is back to default trying to debug this...
Ran Spybot, AVG virus scan, CCleaner, windows defender...

any thoughts???

thanks, finkle