Win 7 x64 SP1. ASUS A8N5X motherboard with an Athalon 64 X2 processor.
I have my hibernation timer set to 45 minutes of inactivity or if my UPS battery level drops below 50%.
For the past week or so, I'll leave my computer to get a snack or something and when I come back it has started hibernating. I restart the computer and it tells me that it shut down because battery levels are low.
There are no power glitches. No alarms from the UPS and the battery monitor shows that the battery is charged.
One thing did just occur to me. This all started after we had a major thunderstorm with a power failure which prompted an automatic shutdown. Is there a flag that didn't get reset?