Computer Shuts itself off- now it won't power on?

[Crypto6]

I recently upgraded the CPU yesterday and the computer was running in perfect condition yesterday and today. I was playing a game and about a minute after I was done playing the game and was exited onto my desktop... my computer powered off.

So I waited about 30 seconds and turned it back on... it didn't turn on. The speaker that will beep never beeped- and the only thing that happens is the LED lights will dimly turn on. I had to turn my PC off by flicking the switch on the power box in the back. But no display- no nothing. The only fan that will turn when it is on is the rear fan and it barely spins. Aside from that- only LED lights from my fans will turn on and its dim. Is it a power box failure?

My computer is custom built!

NEWEST CPU: AMD FX 8350 (Previous one was a 6200)
Motherboard: Gigabyte GA-970A-UD3
RAM: Crucial Ballistix Spot 16GB
Storage: WD RE2-GP 1TB 3.5" 7200RPM
GPU: Sapphire Radeon HD 7870 GHz Edition 2GB GDDR5
Case: Sentey GS-6400 Arvina ATX Full Tower
Windows 7 Home Premium

I only know my power supply is 550W. I had a PC repair place swap the one I have now with one that was defective back when I was building the thing and had issues.

 

[Spykezxp]

Did you Overclock anything (CPU or GPU)? What is the make and model of the Power Supply? If I was to guess, you most likely have a faulty Power Supply. Without knowing what kind of cooling system you have within your PC (Water Cooling or Fans - and how many you have), your setup would be using roughly 425 watts. Now if you factor in Overclocking and your cooling system components, you could be running close to 475 to 500 watts. If you have a "No Name" PSU, you may have overpowered it. Just because it says 550 Watts, doesn't always mean that is what you can draw against it. I always suggest a good name brand power supply that has received good reviews with at least an 80 Plus "Bronze" rating.