2 Blown PSU's when plugging in HD?

So I've had a fun past few days trying to figure all this out.. Bought a new mobo and when seating the new CPU there was a bent pin in the mobo so it broke off one of my pins on the CPU.. So i brought the mobo back and swapped it for a new one, and they gave me a deal on the new CPU! I hooked everything up and computer finally booted but I got a select boot device error, so I check my HD Sata Cables and notice the smaller cable (non power not sure what exactly its called) was pulled out of the plug, the cord itself was all busted on the connector end, when we hooked up my comp I bought a case with holes to hide wires on the back side and it was a really tight fit and realized I probably should've bought a longer cord. but enough rambling here is my issues now... I replaced that cord and computer boots just fine! I had the same tight fit with the larger sata cable so I bought an extender and plugged it in that way. So I put on my side panel and booted the computer, get the same error message select boot device! so I pull my side panel off and see that the larger sata cable (the power is unplugged and my side panel must bump it when I put it on... soon as I plug it in I hear a slight noise and it blew my PSU, so i go by ANOTHER PSU a 750 W Corsair, nice power supply, 120 dollars. I wont bother posting my specs a 750W Corsair is PLENTY to run my comp, I had a 700W OCZ run it for 3 years with absolutely ZERO issues.. Is there a short possibly on the hard drive? Is it a bad board? Any insight would be much appreciated!! The part that throws me off most is originally with my new mobo processor etc and old PSU I had the HD powered and on and everything was 100% fine it booted fine posted fine.. Then when I put my side panel on and bumped that sata power out it all started there, possibly a coincidence but I'm not sure