Media System Corrupt: Fatal Error

Last night while I was watching a movie on my computer, on a DVD, suddenly the media player crashed & error came saying "Update your video codec immediately to resolve this issue".

Error
Fatal Error! The media system on your computer is corrupt. Update your video codec immediately to resolve this issue.
I tried to play another DVD to see, if the problem was with my DVD, but after sometime of playing, the movie again crashed with the same error.
Please help me with this error. I'm using Windows XP & I've Media Player 10 on it.
