Could once watch videos, now all I get is sound with a blank screen...

I restarted my computer, and clicked on some movies that I downloaded to watch them and all I got was a blank screen with sound...

i played some more file video types and got the same thing...
this one time i opened up a clip video and it left an icon on my desktop in a text file titled dxva_ or some crap.. i forgot the file name...

keep in mind i have the latest WMP, I have the latest XP Codec Pack, the latest K-Lite Codec Pack, Latest DivX player, Latest Media Player Classic... direct x 9.0c . latest video card drivers.... EVERYTHING WORKED 100% BEFORE!

can somebody please help

appreciate it..

if i could get the file name of the text file that appeared on my desktop when i attempted to play the video files, it would be great to solving the problem....

PS. QUICKTIME VIDEOS DISPLAY PROPERLY....

THE FILE THAT APPEARED ON MY DESKTOP WAS -> Dxva_sig.txt