Good thing/Bad thing

Good thing: Have jiggered with the firmware on my PC`s DVD drive so that it`s multi-region. Bad thing: An old software install, probably Nero or Virtual CD, has buggered my system so that while it reads DVDs fine it won`t read CDs! Tried lots of fixes, hence firmware jiggering, but looks like i need to rebuild. So, XP or try and get hold of Windows 7?