Anything using Media Player crashes

I just picked up a new cell phone the other day that doubles as a MP3 player. I downloaded Verizon Music software on my PC, so I can synch music to my phone. Every time I tried to run the software after the install it would crash with a Windows crash box popping up. I tried uninstalling, then reinstalling a few times, but to no avail. I decided to try Walmart music just to buy some songs (I've used it successfully before) and it too crashed while trying to load. I then downloaded Napster software to give it a try and I was able to launch it, but when I purchased music it popped up a little window with an action icon saying it was configuring my Media Player. After about 15 minutes I decided the configuration wasn't going to happen. This is when I became suspicious the problem was with Media Player. I was using Media Player 11, so I went to Add/Remove Programs and rolled it back to Media Player 9. Same problems. I manually downloaded Media Player 10 from the Microsoft site and installed that. Same problem. Then, when I tried to upgrade to Media Player 11, it failed toward the end of the install with errors to DrWatson and something else I don't remember. Oh, by the way, I also tried a Safe Boot and it didn't work either. I don't know if it could be an issue, but I recently uninstalled Nero 7 and installed Roxio Basic.

Short of a reinstall of XP, which I really don't want to do unless I have to, I'm at a loss. Can somebody give me some suggestions?

Thanks guys.