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.
As you found out, you cannot easily change the drive letter for a Windows partition because Windows references the drive letter MANY times in the registry. I managed to do it once with W2K, but it took hours to get it to fully boot up.
To fix it right, may require a bit of patience and a rather larger download that you you will find useful for years to come.
If you decide to download a CD image (ISO) file I have posted at 4Shared.com, it must be burned to CD and you will boot with that CD. It can perform a restore point without starting Windows and other very useful things.
It is 159MB in size, but worth it. Get the file I named '2005' by clickingHERE.