None of my software dvd players will work, they are all crashing, please HELP!

I'm going insane. I can't get any of my players to work. They are all crashing. I gave up a long time ago and just started using WMP, but then I got a new receiver and wanted to have digital audio output, so I wanted to try the other dvd player software.

I thought the problem might be with the tv tuner card software Showshifter, which I think part of it was. However, PowerDVD and DirectDVD will not work. PowerDVD crashes when I press play and DirectDVD stops responding. WMP now gives me an error about digital permissions or copyright or something, "more info" says it has to do with the dvd decoder.

If anyone has any ideas I would really really appreciate. This is my only way to play DVDs. If anyone knows of a way to completely rid my system of any kind of decoders that might be installed or tampering with the software I could try that. Please HELP!

-Brandon