I had a similar problem but I know what happened on my pc. Im writing from it now but Im worried if it crashed I wouldnt be able to use it again. I installed xp on my hd and later I bought a 3870x2
but my power supply sucks
so I started unplugging things to see if it would possibly work. After I unplugged my extra storage hd my conputer came up with "Error loading os" After this I cheked the mbr's of the disks in data lifegaurd and it shows my xp hd as nonbootable and my storage as bootable and I have to put my storage as the first drive for xp to boot. I would like to know if I could fix my mbr on my xp drive so I dont need my storage drive.