It isn't impossible to downgrade, I've seen it done. The only problem's that occur are the compatibility issues between XP and your "Built for Vista" hardware... mostly just the BIOS. Like I said, it can be done. You could always bring it into a tech support center, like the one I work at. Staples Easy Tech offers operating system installations. The first downgrade we did took a couple weeks, but it's just a matter of finding all of the drivers. With a tech support service, you don't have to hassle with the troubles of finding them on your own, and the support center is responsible for making it 100% compatible with your computer.