hello, so i successfully upgraded to Windows 7 32 bit professional on release day.  my windows media center worked great and was recording shows perfectly.  i came back to my computer after leaving it unattended for about 24 hours, and it was frozen on the windows 7 OS startup screen (where the four orbs of color form the windows logo). 

 ever since then, both windows media center AND windows media player simply shows a black screen when i play live tv, play recorded shows, or play any video file.   i can hear the audio, but just see a black screen.  i know it's not a tv tuner issue because this applies to ALL video files, even ones that played perfectly previously.  sounds like it might be a codec issue?  i'm thinking my computer crashed and that it might have messed up my installation of media center?  any suggestions