Hi guys, this is my first post, and i'm at a loss as what i should do with my home-made computer. Yesterday i bought the parts for a custom home-made computer, these parts being: Intel Core i7 920 CPU 8GB (4x2GB) DDR3 OCZ Memory 1TB 7200rpm HDD ATi Radeon HD 4870 x2 2GB Gigabyte motherboard EX58-UD4 850W PSU I've set everything up correctly, making sure everything is wired properly and no exposed ends are anywhere near the motherboard. Problem is, when i plug in the 8pin adapter on the motherboard, my computer is constantly restarting, when i turn it on the CPU Fan will spin, the LED's will come on, then 2 seconds later, it'll all go off, it'll then continue doing this untill i turn the PSU off at the back. The wierd thing is, when i remove the 8-pin adapter, the computer will start up no problem, but i see nothing on my monitor at all. I also hear no HDD activity (there is no windows on the HDD, but surely i should hear some activity). When i plug the 4-pin adapter in, the computer will no start at all. I'm wondering if i have a powerfull enough PSU for my setup, and if i do, have i got a bad PSU? I've ruled out the graphics card and HDD as problems, and i've tried with only 1 stick of memory, but it still does the same thing. I really dont know what to do here, it's not the first computer i've built, not by a long way, but this has me totally confused now. Hopefully someone could possibly help me here! Thanks a lot guys!