Friday morning was the first time I’ve ever seen one of my linux machines issue a hard lockup. I wonder if there was a power surge in the evening and it woke up and slept again, so when I booted it, it didn’t know what power state it was at. Luckily, this system seems fine now.

Probably. If the power failure was caused by a lightning strike, that can do damage even if you are using anti-surge/power spike protection. By the way, you have to haveEVERYTHING that connects to your computer using such protection – including everything that plugs into AC that plugs into the computer, directly or via a power adapter,AND the cable that connects to the internet, because you can get power surges or spikesfrom ANY of those sources. If it still has a BESTEC PS, which often comes in emachines cases, it’s even more likely.