Echoing what Rob said, do you have a spare HD?
If so, I would Ghost an image of your Dually configured OS to that spare HD and put it off to the side. Actually, with the newer versions of Ghost, you can burn directly to a CD-R. Either way, this will save you alot of time when you finally get the dually working again.
Then, just do a fresh install to the AMD system and you're back in business.