I think I completely screwed up my laptop
First, I installed what turned out to be an untested beta branch of Ubuntu. Once a helpful person on this forum pointed that out, I figured I'd just install verson 7.10 over it; but I couldn't find an option in the installer to overwrite an existing partition. So, I booted up with PartedMagic and deleted the partition in question, figuring I'd just start over again. But, I think I destroyed GRUB in the process; now, every time I boot up it just stops with the message "GRUB ERROR 22." I can't boot from anywhere, not even a CD, although I'm sure my Windows XP installation still exists if I could get to it. I think I may have completely destroyed it. Anyone think otherwise?