So I just bought a copy of Republic Commando on DVD (for Windows XP) and installed it last night. Today I tried to load my copy of Jedi Academy to do some mod work and the drive couldn't read it. I checked out a bunch of other games and audio CDs and none of them have worked but other DVDs and DVD-ROMs seem to be just fine. Naturally, I'm stumped but I figure a driver or something was installed that's screwing things up. I know it's not a virus because I have no internet connection on this machine. So, I just to get to the point, has any one else had a similar problem or have any more solid ideas on how to correct it?

I have a combination DVD-RW/CD-RW drive. Sony DVD-RW DW-56A drive. I don't have any more specific information at the moment but any suggestions are most appreciated.