Can't play any video

I've had this problem for some time. Tried different formats, codecs, ect...

When playing a video file, regardless of the format, the video will not
play, even on ones it should play 'out of the box'. I can hear the sound fine
on all the formats. The latest one was a WMV. The video and audio codec said
it was WM9 encoded, audio played fine but video would not. This thing won't
play anything except the audio. I also installed the ffdshow codecs which
will pretty much play anything and that didn't work.

I've looked around on Microsoft and other places but most only refer to a
codec problem. I've installed several and even reinstalled WMP11 with no
success. It seems that most of the problem started once Nero Showtime was
installed as part of the Nero 8 package. Nero Showtime would play the files
fine. WMP would not. I already uninstalled Showtime a few days ago because it
was WAY TOO SLOW loading anything thinking it installed something WMP did not
like but it still won't play even formats it should after uninstall. Other
machines play the files just fine even with older versions of WMP.

Any suggestions?