Ok this is my first thread here. I have been building PCs for about 3 years nothing hardcore. My problem is as follows, I was gaming two night ago and all was well. machine got switched off at 3am and was not turned back on till 5pm the next day. When the power button is pressed the fans spin the mobo lights are on as are the gfx card lights but no HDD light comes on this happens for anything between 2-15 seconds then everything goes off! I then have to manualy switch of the PSU from the back lave for 30 seconds and switch back on, the red power light on the mobo now comes back on. As soon as I press the power button I get the same problem. These are the things I have checked so far RAM - Moved all sticks around and checked them in the first slot 1 at a time. PSU - replaced with a Enermax 400w (couple of years old but should be able to power my system) same problem! GFX - have not swapped yet as my old 7950gt is in the loft,lol MOBO - as above, only other one is in the loft CPU - not changed. My rig is outlined below.# MOBO - abit ip35-e shipped bios CPU - core2duo e6600 - stock settings PSU - Hiper type-r 580 watt RAM - 2x1gig crucial XMS2 matched sticks ddr2 I had thought it was my PSU as when i connected it the fuses for the sockets had blown in my house, but now im leaning towards the mobo and this is why (kinda). When I tried the other PSU and was putting my own one back in I had connected all the cables except the 12v one that goes next to the cpu, I powered up the system and all the lights and fans came on except the hdd light, but the system stayed on it just would not boot. I noticed my error and shut it down and reconnected the 12v line, as soon as I turned it on the system shut itself off again like before. i tried this both ways a few times and it was the same with the 12v line connected it turn off immediately. I am now at the end of my limited skills and any help would be great. I dont want to run and get a new PSU if its the mobo or vise versa. Thanks.