reaper_2k9 said:
my uncles motherboard got fried so I am fixing up his pc I bought an asus m2n-mx se plus motherboard for it. Well the first round with it power was going to the board and nothing else the pc wouldn't even come on.
Took it to a co worker who informed me the board was bad. So I sent it back to Asus and two weeks later I get it back.
Now when I press the power button it flashes on and off the fans start the hd starts but then it goes back off. Could someone please help.
If the power is turning itself off after a few seconds, the most likely culprit is a faulty power supply. The demand on the power supply increases as various components fire up; so it could be fine with a few watts for hard drives etc., but as soon as a major component starts demanding serious power, it'll fail.
The only other possibility I can think of is that there's a short circuit being caused. That could be an internal problem with one of the components, or it could be a bad connection. To rule out a connection, take the whole thing to pieces again. First: you know those metal posts that hold the motherboard on? Make sure you don't have any of them where there isn't a corresponding hole in the motherboard. It's easy to leave one in where it's not supposed to be, and it can short the motherboard. Then reinstall everything, as neatly as you can, then switch it on.
As I said, it's probably the power supply. If you could tell us if there are any beeps, that would be helpful. And if it is the PSU, I'd recommend going for one with a good reputation over the one with the highest wattage, check out user reviews. Build quality is really important with these things, as I found out recently when my supposedly bargain 580W PSU blew while playing Fallout 3 recently. My XBox was already with Microsoft for repairs, and it was a grim few days.
Sorry if any of this seems obvious to you, I don't know how experienced you are with these sort of problems. Let us know how you got on.