Computer Won't Boot - Need help? PSU? MOBO?

[51PEG]

Computer was left on for a day. (I can always leave it on without problems). When i checked 30 mins ago, it was off. I thought i turned it off earlier but when i try to boot it up again, nothing happens.

Nothing happens as in no fan noises, no hdd noises, no any noise.

It's a P4 2.66ghz with 1 gig of ram, 2 hdds, 1 dvdrw, geforce 6600gt agp, sound card, lan card. 250watt psu.

I know what you guys will say, 250watt psu? that wont work at all. Well it's been running for a couple of months on the 250watt and nothing happened then.

I replaced that PSU with a new 250watt PSU and it still wont boot up. I thought it didn't have enough power so i only plugged in the mobo and one hdd. Still nothing.

The lights on the mobo are not turning on when i switch on the psu.

What should i do? What could be wrong?

First thing i'll try is to buy a better PSU with like 400 watt. But i dont think that's the problem since it wont even boot up the mobo + 1 hdd.

 

[stevty2889]

If the lights on the motherboard are not turning on when you switch on the PSU, then either the PSU is bad, or the motherboard is bad. Turn off the PSU, unplug it from the motherboard. Leave it plugged in to a hard drive. Short the green wire to any black wire, then turn the switch on the PSU back on. It should come on if it's good, if not, the PSU is dead. Running a system with an underpowered PSU, is what will kill a psu, so replacing a weak PSU with another weak PSU isn't gonna fix anything..and can damage other components as well..my guess is the new PSU was too weak as well, or was already dead. The only time I had a problem where the standby lights on the motherboard didnt come on, was from a dead PSU.

 

[51PEG]

Can you clarify on which green wire and black wire are you talking about? is that the wire that causes it to power up?

 

[DrMrLordX]

sounds like your mobo fried actually. Do either of the PSUs you're using have fans? Do those come on at all when you turn the power on? Just curious.

 

[51PEG]

Both PSU has an internal fan. Both wont turn on when i try to turn on the computer.

 

[montag451]

Just to check - can you check that the fuse in the plug of the power cable hasn't gone and try something else in that socket to see if it isn't the socket that is broke.
Also, try another power cable.
Then, if still no luck, trip any green wire (4th wire) to any black wire.
If no go on that one post back.......

 

[51PEG]

I did in fact try another black power cable already and it wasn't that. I'm kind of afraid of tripping the green to ground. Paper clip with tape for handle, would that do it?

 

[stevty2889]

That would work fine. Just make sure you have it attached to hard drive or something, you don't want to power it up with no load at all.

 

[51PEG]

Okay, tested stuff out.

New 500watt ps didn't power up the mobo. But when i loosely connect the power to mobo, the led on the mobo blinked rapidly(usually it stays on) and the CPU fan spins up at a low speed, not as fast as it woudl be when the comp is on. I tried to hold it in this loosely connected position and push the power button, didn't work.

I really think the mobo is dead.

 

[stevty2889]

I agree at this point it sounds like the motherboard is dead, but it could be dead because the first PSU which was underpowered for that system blew and took it out..I had a motherboard die that way.

 

[51PEG]

I'm going to see if i can RMA this with ASUS. Can't believe they dont have a toll free number.

 

[51PEG]

mobo RMA'ed. Put in my CPU(which about 20 pins were bent during the process of taking out the HSF(it was basically glued to it). so when i tried the cpu in the rma'ed mobo... things come on. except there's no beep and no video signal. all fans worked. let it stay on for a few mins then shut down. cpu is ice cold!!!!

Gave up on this set and caved into the overclokability of the semprons.