I've got a low-end machine for testing our software. It needs to be tested under various versions of Windows, so I was planning installing each one on its own partition.

Then I realized that after testing our software, I'd want to roll back to the previous, clean state. I don't want to use any virtualization software because it tends to interfere with the workings of our app. That said, what's the best way to achieve my goal? Norton Ghost?

Edit: I work for a pretty monstrously huge organization. Money is no object here (and sometimes, if the wrong people get wind of it, "open source" software is bad).