I have a problem, obviously.

Is there any way to boot into DOS from XP? It's pretty complicated, but, I need to clear the CMOS. Normally I'd just open up the computer but it's my sister's and it has that warranty seal on it that she wants to keep. For some reason the BIOS has a setup password (no boot password) and I can't change the boot order. So I'm stuck booting from the harddisk. The ideal solution would be to modify the boot partition somehow and install DOS (partition magic could do this im guessing). That way I could boot into DOS and run my cmos-clear utility (w00t) and voila, no setup password and I can therefore restore her computer (XP is broken). So, to sum things up, is there a way to boot into DOS from XP? (with read access from C: drive)