When I got home from work we dragged it into the other room and tested it with a different cord, yielding the same results. Fortunately I had a spare 480W Antec power supply in the closet. We should probably have a slightly beefier power supply in her machine, but as long as this one doesn't seem to be overheating, we'll leave it be for now. Antec usually builds a pretty solid unit. I think I may have a slightly larger (650W) Everex sitting in a spare computer in the closet.
Luke Skywalker appeared on my desk at work sometime during the night. Nobody seems to want to lay claim to him, and nobody around me will take responsibility for leaving him there. If he has not disappeared by the weekend then he will be moving desks with me.