Dying PSU or mobo?

At first (Saturday) I thought I had just not pressed the button on my tower to start it up, and yesterday (Sunday) it took a couple of presses to start up but I didn't have time to check it out. This morning, however, my computer will barely start up if at all. After I press the button the fans rev up and then run rather weakly before it shuts down (the LEDs also run). I took my computer apart today and dusted it out and made sure every cable was tightly in place and it still doesn't work. I did manage to make it to the motherboard screen but it shut down immediately as it ended.

I have Windows XP SP3, 4 gigs of RAM, Intel Q6600 @ 2.4ghz, GTX 260, ASUS P5N32-E SLI mobo, and a OCZ GameXStream 700w ATXV12 24pin PSU.

Thanks for you help

Looks like a MoBo problem.


Had that with my old laptop.

Then again, yours is a tower, not a laptop, so I'm not too sure.

It sounds like it's not getting enough juice, so I'd guess it's the PSU.

Just had the exact same problem and replacing the power supply fixed it. 

Trevty said:

I agree with Calodine.  Try replacing the PSU and seeing what happens.  If worse comes to worse, all you've lost is the time to get it and it's the far cheaper option than replacing the whole mobo.

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This. Try the easiest thing first.

Generally if it's a power issue you should get a BIOS beep code, unless it's not even making it to POST.

Protip - your mobo has a green LED between the PCI-E slots which checks the PSU voltage. If it's steady green it's fine, if it's flashing you have a problem with the PSU.

The motherboard lights don't come on (there's usually an orange one in the back of the case by the USB ports and stuff) when tis plugged in and I switch the PSU to on. Only light that does come on when I press the button is the blue LED in the front of the case. My CPU fan comes on though, but it doesn't sound strong although the sound

I don't get the POST beep either.

EDIT: PSU fan still speans, weakly. And the green light on the mobo (finally found it, it was hiding near the bottom under my sound card) is steady HOWEVER my mobo manual does not make any mention of it flashing, only on or off. There are also flickering blue light(s) in the PSU but Im not sure if that is from it or a reflection of the blue LEDS at the front (somehow).

I don't have a spare motherboard or PSU to test.

The green light is monitoring standby power. If it's on the PSU is supplying it. If it's off it isn't, flickering indicates intermittent supply.

Easy way to check is to unplug everything but the two mobo power connections and try to start. Listen for the beep from POST. If it starts fine, turn off and start plugging everything else in till you find out what's borked. If not it's either the mobo or psu, if you don't have a multimeter to check the PSU current then I'd suggest replacing it first.

I don't have access to a multimeter but leaving only the mobo & cpu plugged in still the same thing. The PSU's fan is definitely not running as it should be. So I ordered a new one (Corsair TX650w), I don't plan on upgrading anything for at least a year anyway.

FINALLY got my new power supply, everything works great now Thanks for the help!