Okay, so, all I wanted to do was change my main HD from H to C (for some reason when I installed XP, my main HD was set to H). In the adminstartive tools, it said I can't change the letter of my main drive. I did it anyway in the registry....I restarted the computer to get the changes to take effect. Everything seemed fine all until the login screen. The XP GUI bootup screen came up with the little loading bar and stuff, but after that I get a blank screen and the computer reboots. In safe mode, I can get a little further, but still not far enough. I DID make a system restore point before the letter change, but I can't get into the OS to restore it. In safe mode, I get all that DOS looking stuff, and then I get to the login screen but it just has the XP logo and it stays there forever. I'm guessing I CAN fix it, considering the computer seems to be able to somewhat read XP, and I can still get into the BIOS. I just need some help. Any help is greatly appreciated.