this is going to sound like an odd quesion, but how heavy was the power supply?
yes it is possible for power supplies to fail catastrophically and take parts with it.
my last computer had three of the same antec power supply die in it, and after the last PSU failure I decided not to RMA when it took the GPU with it.on the box i think it said about 3 lbs give or take half a pound. not exactly sure but that has to be close
that sounds kinda light. my 950 watt PC power&cooling(actually 1000 watt@12 volts) weighs about 7.5 pounds. that thing is a burly beast.
your PSU might not die on you but I wouldn't trust it with more than a 500 watt system and even then I wouldn't be sure.