I just purchased a TX750 V2 PSU, 4 gigs of ram and a GTX 560 to upgrade my computer. When I installed everything the computer worked great. Fired right up. I used the computer fine for about a week then when I went to turn the computer on it lit up and started then turned off maybe 5 seconds later. I then checked to make sure that all the wires were seated properly and they were. I then turned the computer on, it turned off. I unplugged it, then plugged it back in and it ran fine. I was able to be on it for about 3 hours. I then turned the computer off cause I left the house. When I came back about 3 hours later it started then turned off immediately. I then opened it up and checked it and now sometimes I hit the power button and it doesn't even start. Is it my power supply? or should i take the PSU out and then plug it back in? I don't know much about PSU's please help