Thermalktake 750watt Blows when Flipped !

I had my Thermaltake 750 watt bronze for about 3.5 years. I noticed how the psu`s are shown on the web sites fan on top. Now this psu was in a Coolermaster HAF 922 but was on carpet. So I felt bad for it maybe not getting enough air flow so I flipped it. All was fine for 1.5 days and I felt better as it inspired confidence with fan up. Well last night I heard a loud bang and pop and the whole system died. I went down to local Tiger Direct and picked up a Corsair HX850i , wich is something I wanted anyway. Why did it die only 1.5 days after I flipped it ? The fan was running all the time on it. Could a drop of water from my new Corsair H100 cpu Hydro cooler maybe dripped down into it and shorted it out ? To be on the safe side, I installed my new psu face down ! Corsair tech support said the Hydro cooler does not drip ! Thanks.