Updated Media Player and now all my .mpg files are corrupted?

Recently updated my windows media player to version 11.0.5721.5145.

Ever since, all of my mpg files will not work. I'm given the message "A General Error Has Occured - Unspecified Error" when I try to play them in Real Player. The streaming test vids on the Real site work fine, which leads me to believe the problem is specific with the actual files on my comp.

When I attempted to play the files in media player itself, I'm given an error message saying Windows encountered a problem while trying to play the file. When I click web help, it tells me that I've encountered error message C00D11B1.

It suggests updating my sound drivers etc.. but this doesn't help as my sound card and drivers are fine.

I am running with an XP Home Edition 2002 on my comp, if that matters.

I would greatly appreciate anyone who can help me out with this. I have a considerable amount of important files which I fear may now be useless! :-(