My apologies, guys. I think everyone might be able to ignore this entire thread. The latest problem I posted about was traced to a bad backup battery. Once I got to the computer this time I was able to see that when the printer kicked into gear to warm up the fuser, it was clearly drawing more than the little old backup battery could stand, and cutting power to everything plugged into it. Once I ripped the battery out of the mix everything worked fine, and the computer actually seemed to be running a little snappier, but we'll see. I might upgrade the memory anyway just to be safe.

Thanks, though, for all the help here.