There's a number of posts about at the mo with the same symtoms as this. The machine seems dead. It doesnt beep on POST.
Everything is out of it at the mo and there's literally only 1 stick of RAM, the cpu, and the HSF plugged in. It's still knackered i can tell because my memory is the one from corsair with the lights on the top of it and when you turn the system on this light is stuck on orange, no activity, nothing (the same as with the other peripherals plugged in). The memory is fine, it's been tested. So is the graphics card along with the hd's and there cables. The PSU is a brand new RMA and it's been working until about an hour ago - i tried a different one anyway. no joy.
It started playing up after i took the sata cables out of 3/4 and put them in 1/2 (not overclocking at the time). I also took my sound card out and put in on the metal inside the case - the 5" drive bays - i then reset the cmos, returned the jumper to normal position, and turned it on... dead.
It also just turns on by itself all the time now just by switching the PSU switch (not the computer power switch), the same as it does after resetting cmos.
I dont know what else to try apart from stripping it down to bear minimum and seeing if it works, but ive done this and it doesnt work. Any ideas?