Comp won't turn on right after shutting down?

[Brains]

So I have pretty much had this problem forever.
Whenever I shut down my computer (for whatever reason) and then go to try and power it back on again (whether it be 2 seconds after power down or 5 minutes later), the computer won't turn on. There is power going to the mobo and the LEDs on the board light up correctly but when I press the power button, nothing happens. BUT when I just leave it off for about ~11minutes (I disconnect the power cord and flip the PSU switch) and then reconnect the power cable and flip the switch to on on the PSU, it starts up no problems. Like I have to wait for the excess charge to disapate from my system or something?? It's weird. I even sent it back to the company I bought it from and they replaced the mobo (fixed another issue I was having) but I still have this problem.....

Is it even a problem or is this how custom gaming super computers are now?

system specs:
CPU - q9550 @ 2.83Ghz (acetec liquid cooled)
PSU - 1000w toughpower
GPU - GTX260 (x2 in SLi)
mobo - nforce 780i SLi
RAM - 8GB ddr2 800 corsair

[stewlounse]

That shouldn't be happening. Sounds like it may be a power supply problem. Do you have another to try out?

[stewlounse]

What happens when you turn the power on, then hit the reset button (if you have one)?

[darklight]

I've seen behavior like this before when I was clocking my cpu or memory too high. I think it could be a temperature issue. I agree it could be a power supply problem too.

[Freaky_Angelus]

Update bios..

serious, that is it... Updated my pc with a HD 5770 last week and had EXACTLY the same, turns out it is some weird GPU problem older mobo's have with the newer cards.. Reading the 780i is nice, but with a Q9550 means you probably run this for almost 2 years or so now.

Wild guess, ASUS as brand? If that hit the spot, try a bios update ;)

[stewlounse]

Yeah +1 for BIOS update...when there is a funny problem I always check for a BIOS update before trying to mess with anything else.

[Brains]

I bought this computer in August of 2008 and it's an EVGA board.
I kept assuming it was a PSU issue but it's pretty expensive for 1000w+ PSUs (going for triSLi).

also stew, when I press the restart button while it boots up, it reboots like it should. the only problem comes when I completely power it off (whether it be correctly through Start -> Shut down or some other way like losing power in my household or doing a manual shutdown by flicking the PSU switch).

I've been meaning to check it through replacing the PSU but like I said, quite a bit of money for another capable PSU when this one works fine, just has issues if and when I have to power my comp back on right after it going off...everything else works fine. the PSU never faults at any other time.

I've also done this test (http://www.cyberpowerpc.com/forum/forum_posts.asp?TID=2881) which my PSU passed. so I don't really know what it means for my situation whether or not my PSU could still be faulty right after being shut down. It's goofy. the only way I'll probably really go out and buy a new PSU is if my system just doesn't turn on at all OR if my system is underperforming right now. would be awesome if someone had a very similar system like mine so I can compare to see if my system is as powerful as theirs.

EDIT: also it shouldn't be an overclock issue (everything is at default timings/multipliers from manufacturer); same with temperatures since I monitor the temps all the time because I do alot of 3d rendering where my CPU/GPU max's out during that time and the CPU is liquid cooled and is always lower than recommended temps and I have 4 12mm fans over my two GPUs directing airflow.

[stewlounse]

So when it is off and you turn it on...the LEDs come on the board...does the screen turn on? or does BIOS even show...or does it POST?

[Brains]

when it's powered off (power cord still connected and PSU switch ON) there is a blue LED on the mobo showing it is receiving power (good thing). when I press the power button, a green LED lights up on the mobo (which remains on the entire time my computer is actually powered up and running). the problem is when it shuts down (in whatever fashion), that green LED stays on when it should be off. this is where I figured out to disconnect the power cable and switch off the PSU and leave it off for a while. I've timed it out to be around 11 minutes where then I can reconnect it and power it on with no hiccups.

so when this green LED is on when I try to power it up, nothing happens. the very first time I try to, the fans spin for like 1 second and my HDDs spin up for like 1 second too then everything stops and only my green and blue LEDs are on. if I try to press the power on button again right after it stops, nothing happens, no spinning fans or HDD just those 2 LEDs stay on. until I disconnect everything for a while then reconnect and power on.

EDIT: also, when I see that the green LED is on (when it should be off) and I disconnect the power cord, if I reconnect that power cord and switch on the PSU before that special 11 minute mark, the green LED comes on again when it shouldn't. so my guess is that the current in the system hasn't dissipated completely. I know computers have a killswitch built into some PSUs that if it detects a surge in the system, it won't allow the PSU to fire up. my PSU comes with that functionality. It's a good thing, but it's gay since I can't figure out where the surge is coming from (if this even is the problem). I thought I might have a screw from the mobo touching the metal frame inside the tower but having this problem even after the guys who replaced my mobo at the manufacturer replaced my mobo is highly unlikely.

[stewlounse]

Damn man...

So are there any BIOS updates available for your mobo?

See what this does... Next time you shut it down, leave it plugged up but turn your PSU switch to off, then hit the power button a few times and see if it drains that power out.

[noclass]

You could also try running at the minimum to see if any hardware is causing it. Like unplug all additional HDs other than the one with the MBR and OS along with taking out any sound cards, NICs, etc... If you have an onboard video, use that to test it out and remove you vid card too.

Its tedious but if it still occurs at least you narrowed down the possibilities.

I had an issue once where my PC was hella slow, turned out it was my other HD ,which i kept my pagefile on, that was the cause since it was dying.

Sometimes its so obvious that you wouldn't think that it would be the cause...

[$uCkY-p|aYeR]

Ok, going to take a stab at it.. If I understand this correctly that the green led should be off when the computer shuts off. If not then I am to understand that the computer isn't shutting down completely. Now if you were to shut the computer off in windows with out going thru start shutdown. You would have to hold the power button in for like 2-10 seconds then it would hard shutdown. I believe it is something to do with the bios possibly but it could be something hardware not allowing the computer to completely shut off.

Try this not to fix it but to give us more info after you click on start shutdown and the computer seems to be shut off. Try holding the power button in for about 10-15 seconds or until the green led turns off. If the green led turns off then try to turn the computer on. I have had several computers even tho they appeared to be shutdown something was stopping it from completely shutting down. But none of the computers that I have seen this happen consistently done it or I would probably have a fix for you.

[Brains]

Well I'll go more into depth with this now.

Situation A: I turn off the computer correctly in Windows.
Computer will do it's normal routines and shut down. The green LED on the mobo goes off (like it should), blue LED stays on (light it should) and everything seems perfect. If I press the power button on the front panel to attempt to turn it back on, the green LED comes on (like it should) and the fans/HDDs will spin up for ~1 second and then go dead. The green LED remains on though. The computer sits silent.
Situation A fix:
I unplug the power cable from the back of the computer, wait for ~11 minutes, plug the power cable back in, blue LED goes on and when I press the power button, everything boots up normally.

Situation B: Power outage or some other reason for computer turning off out of my control
The computer will lie completely dead. No LEDS are on. I will then wait for the power to come back on or wait for whatever the issue was to resolve itself and then attempt to go turn on my computer again.
Situation B fix:
If it has been more than ~11 minutes since the issue happened, all I do is press the power button and everything starts up normally. If it has been less than ~11 minutes, I'll wait the necessary amount of time until I hit that magic wait time mark. Then turn everything on.

**At anytime after my computer has shut down/turned off and before that ~11 minute mark, if I go to turn on my computer, on 1st attempt the fans/HDDs will spin up and the green light will come on. Then everything goes dead except for the LEDs are 1 second. If I don't disconnect the power cable and do my fix and I try to just power it on again after failing the first time, absolutely nothing happens. Also, if I hold the power button (when my computer is "off" and won't turn on at all with the green LED on) then after 5 seconds or so the green LED goes off. So now if I try to turn it on, the green LED just turns on and nothing else happens.

I've also tried different combinations too like power button w/ power cable connected and PSU switch off, power button w/ power cable disconnected and PSU switch on, holding the power button with connected/disconnected power cable and PSU switch on/off. I've also tried with just 1 video card connected, with just my OS HDD connected, dust, faulty connections, etc etc. I even had my whole tower shipped back to the assembler where I bought it from to replace the mobo over last summer and even right when I got it back, it still was having this problem.

[stewlounse]

I still kind of think it may be a BIOS or PSU problem. The discharging over 11 mins, if that's what it is, could be happening inside the PSU instead of something with the motherboard (PSU's get tricky sometimes). That may explain why replacing your motherboard didn't fix it, but I can't really tell you why it runs like a charm after 11 mins.

Make sure your BIOS is the latest version is probably the best advice so far.

[$uCkY-p|aYeR]

OMG yes that is crazy problem.. I don't have any ideas but would have to lean towards the PSU also.. Since MB been replaced. If you ever do find a fix please post it..

[Brains]

I'll check out the BIOS tonight. If that's not it then maybe I'll have to poke around and see if any of my friends has a power supply I can test out before I go and shell out money for another 1000w PSU.

[Freaky_Angelus]

Well considering that it is a constant waiting time no matter what I would say a PSU only problem..

What you mention is a capacitor that needs to discharge before you can reboot.. (hence 11 min.) IF you know someone with a PSU you can borrow this should be an easy test.

My restart and BIOS related problem on videocard was not a constant time, it was more a random reboot time and unplugging the powercord would not influence that randomness.. It looked like a cap giving some false signal, but it was way more random then a stable 11 min (besides.. 10 ~ 60 sec is still acceptable ;) )..

So.. If you can, try to switch the PSU with another.