I'm not sure what's wrong exactly, but recently I've been having a problem with wmv files. At first I thought it was just WMP, but MPC has the same problem. VLC plays them fine though.
Here's what the video looks like:
you need wmp 10..mine does the same with 9...dunno why...perhaps the onboard video
But that doesn't explain why it doesn't work with Media Player Classic, does it? That screencap is from MPC.
Looks like a codec issue. Have you tried installing the WMP codec pack from MS?
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I installed one. Then I let it install an update. It's working ok now. It used to work fine, then it stopped.
I thought MPC came with its own codecs.