OK, /dev/sda1 is mounted on "/media/DED8216ED82145DD". You can take a quick look at it and verify that it's OK, but I can't think of any reason it wouldn't be, since it mounted.
Looking at your df -h, I see that "/" is mounted on /dev/sdb5. That still indicates to me that you have changed the BIOS so that SDB is the boot drive. I'd check the BIOS and see if you can set it back to SDA, which I take to be your internal drive. With any luck, it'll boot, unless I've skipped over something when reading your post. Otherwise, you'll have to follow syg00's and yancek's advice to boot from a recovery disk and run fixmbr or fixboot.
Still, I'm surprised it won't boot from grub, unless you've really made a hash of the XP drive.
Last edited by Quakeboy02; 02-14-2010 at 11:46 PM.