Computer just switched off at random, for the second time today. This time, it happened simultaneous with a power flux event (the air conditioner halting).

Maybe I need a UPS. :(

Just happened again. Third time today. Second time in an hour? No other electrical devices seemed to have any problems. I guess I should officially be worried. :(
@mcc how does the PSU smell?
@Farbs I checked! Totally normal!
@mcc @Farbs Sounds like time for a UPS. Sometimes mine will click and whirr even if the lights never visibly flickered, and then I discover the media PC upstairs (which does not have a UPS) has rebooted.