Diagnosing Power issues?

I have a very interesting power/motherboard issue. The reason that I say power/motherboard issue is that I don’t know whether it is the motherboard, the Power supply or the power on switch in the front of my case is the problem. The computer is very new, built no more than 2 months ago. It has worked perfectly till 2 days ago when the weirdest thing happened. I shut down my computer before I went to bed like I do every night (I shut it down through windows and then when it is off I turn off the switch in the back). Morning came and i went to turn it back on and I got nothing. No beep, no fans spinning up, no nothing. So I immediately thought my power supply was bad. I made the trip to comp-usa and bought a new power supply, the exact same one that I had in there before (Antec Neo-power 480). I installed it and hooked up everything the exact same way i had it before and i still got nothing. I am now thinking that the gremlins got into my computer while i was sleeping and messed up my motherboard or something, but i now think that it is my motherboard that is bad.


I don't have any idea of to what would cause my computer to just not power on all of a sudden with no changes made to the system at all. I have replaced the power supply and that doesn't seem to change anything. I'm assuming that since it isn't the power supply that it must be the motherboard or the power on switch on my case or is the something else that i am not considering? Any help would be appreciated.

Computer specs:
Motherboard: Gigabyte GA-K8N ULTRA-SLI
CPU: AMD Athlon 64 FX-55
Power Supply: Antec Neo-power 480
Video: x2 Gigabyte 6800GT GV-NX68T256D-B
Ram: OCZ 1gb (2x512mb) EL DDR PC-3200 Platinum Revision
HDD: 2x Western digital 74 GB SATA 10K Raptor

Again thanks for your help in advance

Stoopid question, I know, but you'd be surprised how many people get tripped up by this... did you try plugging the computer into another, "known good" electrical outlet? That goes for the power strip, too... I've seen people going full-bore into troubleshooting their equipment when all that happened was the integrated breaker on the power strip popped.

I have tried this, one of the first things i did when i came upon this problem. The computer is also plugged into a UPS that is brand new as well. The monitor and cable modem/router are plugged into there as well and seem to have power running to them and work just fine. I could see how a lot of people would trip over something as simple as checking the outlet for power. I work in computer retail and i find a lot of the time something very simple will be missed in the troubleshooting process. And it kills me when i hear about someone spending a ton of time trying to fix their computer when it was something as simple as have a bad outlet or even forgetting to plug thier computer into the friken wall . I thank you though for your reply

Edit: the remark i made about hearing a story bout someone forgetting to plug there computer into the wall and trying to troubleshoot it for about an hour is a true story i have heard at work. Funny stuff

I watched a tech bang his head against a component for an hour before he realized that he forgot to turn on the power switch, it was pretty funny, but we've all been there.

Find the connector where the switch plugs into the motherboard, pull it off and bridge the two pins on the MoBo with a small screwdriver. Be sure not to contact any other components, of course. This will eliminate the power switch as the culprit.

Alternatively, if you don't feel confident about the scewdriver thing, you could plug the reset switch into the power pins and try powering up using the reset switch.

Barring that, then you likely have a processor or motherboard failure, as you surmised.

Thanks for the reply. I reset the cmos and tried manualy to switch on the power useing a screwdriver. But he same effect happened. No fans spinning, no nothing. I am pretty sure the motherboard died somehow in the night. What would cause a motherboard to go bad all by itself when its not even on? Thanks for your help though i do appreciate it. It looks like i will be useing the warrenty service on the motherboard(JOY!)

Im pretty sure it's the PSU actually...

grab a 3pin-fan->4pinpower connector and see if the fan runs when the CPU is on.

Thanks for your suggestion. Sorry if i do not understand your reply. Could you explain a little bit more on what to do exactly. This is PSU that i have it hooked up too is brand new just bought it yesterday and is that same exact one as i had before. Do you think that i could have gotten 2 bad PSUs from Antec? I guess it could be but it just seems hard to belive. Is there any way to test once and for all if both my PSUs are bad without hooking the 2 antecs that i have to another computer (I unfortunatly don't have another computer to test it on at the moment). If you could elaborate on your method of testing i would try it right away. Again thanks for your reply and i hope to hear from you soon.

if you got a new one, its unlikely to be broken...

Mobo issue then...

Magic? I don't know, but that's what warranties are for. Good luck and let us know how it turns out.

I fixed it! Apparently some of the usb ports on the front of my case are damaged and are causing a short in the motherboard making not want to turn on. So i disconnected the cable that led to the bad usb ports and vola, success! I found this out after a bought a new PSU and motherboard for it and have the old Motherboard on rma. Oh well at least i have some much needed upgrade parts for my older PC.

Thanks for the reply back... at least it's something simple and you know what went bad

It may be an old thread, but boy was it ever helpfull.

My machine showed no signs of life last night at all. I swapped out the current PSU with a spare, and still nothing. I put a meter to the current PSU, got 5V to the switch, got continuity through the switch, and resolved the problem was possibly motherboard related and probably more costly to fix than warranted for this circa 1999 work horse. In a final attempt toward trying to diagnose the problem, knowing sometimes simple things get overlooked, I stumbled upon this thread.

I hadn't considered something may be shorted or bad beyond the motherboard, except for perhaps the processor. Within 180 seconds of reading this thread, my V92 modem (almost 2 years old) was out and the computer began to spin up. Many thanks to all

I had problems with the CPU fan running at full speed to keep the CPU cool when i had a good few programs open. Its a Pentium 4 2.8GHz 64 bit, with 6 other case fans for cooling. I decided on purchasing a new case with 2 140mm fans to improve cooling (and noise levels) and transferred all bits into the new case.

Everything hooked up, hit the power button and nothing

A bit mad, i re-seated everything, fan, CPU, memory, power leads, but to no avail. I then decided to start unplugging everything i did not need, hard drives, DVD ROM, DVD writer, fans and only had the main power block for the mother board, and the 4 pin mole connector, and i believe, a square 4 pin block that powers the processor. Still nothing.....

Tried 3 different processors and 3 different CPU's. Still nothing..

I unplugged the square 4 pin plug (processor power supply?) and hit the power button, and it powered on. After numerous plugging in and out of everything (about 4 hrs of it ) still nothing.

Only thing I can think of is the motherboard.

Any ideas people