[Augustocba]

How to fix if WMP 10 in Windows 7 is not able to play MP4 and some other video files.

Even after installing K-Lite Codec Pack, my Windows Media Player was not playing some of the video files I have. It did not play any mp4 files, and did not play some mpeg and avi files.

Here how to fix this:
1) In K-Lite Codec Pack program group, find and run "Codec Tweak Tool".
2) Click the button "MS Codec Tweaks"
3) Check the first option ("Disable Microsoft DTV-DVD Audio Decoder").

And that's it! After disabling Microsoft DTV-DVD Audio Decoder, all my video files play perfectly in my WMP10 under Windows 7 32 bit.