Well, I was wrong, and the Gateway techs were right. The power supply was sick. I had the machine back three days later, and it would have been only one day except that I didn't call my office to find out that they'd left a message saying come pick it up. So I picked it up, brought it home, put my drives back in, and copied the parts of my life that were temporarily moved to the laptop back to the Gateway, and all's right with the world. Or at least with the Gateway.