My friend sent me a video of him biking and it's an MPEG2 format video, but it wont play. I've used G-spot...

to see if I have the right codecs to play it and apparently I do but WMP wont open it, it says "Windows Media Player cannot play the file. The player might not support the file type or might not support the codec that was used to compress the file." How can I open this file?