Ah the joy of computer hardware.
I am so glad my PC posted first time both when first built and upgrading GPU.
So, try to turn on the PC with the GPU pulled out. If it beeps and starts, then you know the GPU is faulty.
Originally Posted by Myyr
Quoting this and bolding it cause it's been said like 12 times so far and OP keeps ignoring it instead listening to the morons saying LOL PSU IS FRIED RETURN IT.
Do this first. Before anything else. Always start with the easiest/fastest things first. You're going to feel like a fool if you go buy a new PSU plug it all up and the same thing happens when you try to turn it on.
Do that first, like these guys said.
Anyways, buy well known PSU's from Manufactures such as Antec, Corsair and Cooler Master.
No name PSU's often lead to a dodgy demise. Also don't switch from 230(UK, I'm a Brit) to 115(USA) volts like I did (at least whilst there is still capacitance) or you will hear a loud bang, proceed to need a new pair of boxers/pants and a new PSU/PC (PSU smoke, don't breath this).
As has been stated before it's generally noted that your PSU wattage will probably need to be GFX Card recommended + 15% rounded up to the nearest 50. For instance I have a 560ti, 500W recommended so I can get along easily on a 600W Power Supply (I use a 700W since I wanted to be super safe, potentially using it on other builds down the road)
You on the other hand should be fine with a 550W PSU but honestly the 520W should be working fine for now, you should only be seeing problems later down the road when the real output wattage comes down from degradation of the parts inside the PSU leading to more frequent blue screens and eventual death of said PSU.
For now I would go get a replacement PSU from the place you bought it and see if that wants to work. If it doesn't then go buy a better made PSU from people like Antec from a dedicated computer store since best buy probably sold you their own made PSU or something.
Good Luck! (Pic relevent to post issues when doing PC hardware stuffs.)