PC won't boot

[kylven]

I've had this problem before, about a month ago just after i built the PC if i turned the system off it would not bootup upon hitting the power button. All the lights and fans would come on for a second then all would turn off. I would then need to flip the switch in the back off for bout 7 seconds then turn it on and hit the power button. It took me about 30 tries but it finally turned on and stayed on. I can reboot fine as long as i didn't turn the system off.

Now I woke up this morning and the system is off. I tried to turn it on, same symptoms as before except this time i've tried 100 times and i'm getting no where. Here are the things i've tried:

I've unplugged everything and reset everything.

I've reinserted all cables and cleared what dust had built up.

I've tested the powersupply with minimal hardware, fan runs fine, but then powers off as usual.

I've tested the RAM and dimm slots


I'm not sure if this is a cpu problem or mobo or powersupply, they all seem fine. My pc had same problem before and booted eventually leading me to believe its not the cpu causeing this. I really don't know everything seems fine all lights on during the second its powered up. Any Ideas?

[Restek]

It sounds to me like a power supply issue - do you have a spare you can test with it? The second most likely candidae would be the motherboard, but my money would be on the PSU for starters.

If it is the PSU, on the bright side they're quite cheap