Dual boot XP/Ubuntu with Ubuntu on external HDD
I have already installed Ubuntu on my external drive, it works and I can also dual boot XP fine. However, when I unplug my external drive and try to boot into XP I get a Grub error (I think it was error 21, Ill confirm that and edit if needed). I would like to be able to dual boot whenever my external drive is plugged in but also be able to boot XP when the drive is unplugged. I am sure this is possible, and I hope that it is possible to do without reinstalling linux. Any ideas?