So, about 3 months ago, I built a second rig, designed to be my primary gaming PC moving forward. It's worked fine until about a week ago, when I went to power it up and for some reason it refused to boot. Power's there - the fans start whirring and I can hear the HDD drives spinning; lights also appear on the graphics card and motherboard, however none of the peripherals (such as mouse, keyboard, screen etc) power up. Additionally, if I leave the peripherals in and go to power down, I simply have to press the power button and it switches off. If I take them out, it seems to do more, namely that if I want to switch it off, I have to hold the power button down for 5 seconds as usual. As I cannot get to the BIOS, I can't do a beep test - I've ordered a POST card, but it's not arrived yet. My theory is that the PSU's died, unusual as it's a Corsair - a brand I've never had problems with in the past, and being 3 months old, I'd have figured that it's got a long way to go before it should expire. I have an older rig with a GS800 that I could cannibalise, but I'm not sure the amp's on that can support the GTX780, which means taking that out and using the GTX570 from the older rig too - not the end of the world, just a hassle. My question is; from the the information supplied and the forum's own opinion, what further tests can I do to identify the source of the problem and does anyone have any suggestions as to what this issue might be?