You keep saying that you are not getting any beep codes. Does your case have a speaker? If it doesn't you won't get beep codes. You can purchase a case speaker replacement at www.bestbyteinc.com. It doesn't require a case speaker to operate and attaches to the front panel where the speaker connnection connects.
I installed a speaker on the motherboard when I was having that problem.
I have a Corsair 520w PSU. I have already sent the GPU to newegg for a replacement. I was concerned the 7300 was working on what could still be a faulty PSU so I picked another one (PSU) up at Best But and no dice on that one either. Is it possible I got two faulty PSUs? Yeah, but I figured unlikely.