Computer won't turn on - Dead CPU?

[tincantuna]

Initial hardware - i5 2500K, Gigabyte Z68P-DS3, 2x4GB G Skill Ripjaw RAM @1600MHz 9-9-9-28, Zotac GTX 970 and Corsair AX760. 

 

I have struggled to find this issue anywhere online so here goes... In September I suffered a random shut down. My computer then didn't turn back on straight away. I had to unplug the PSU to discharge the computer before being able to turn it back on. Over time the problem worsened to the point where it needs to be unplugged from the wall for 24 hours before being able to turn back on. 

 

PSU - I previously upgraded my Corsair TX750 to the AX760 on my quest for silence. I have tried both power supplies and I still can't get the computer to turn on without discharging fully. These power supplies do work on other computers (the TX750 is now sold to a friend which is running perfectly in a Skylake build). 

 

Motherboard - As the problem became more serious, I scoured forums and thought the motherboard was at fault. I have cleared CMOS and removed the battery for 24 hours at a time, still the same issue. I have replaced the battery with a new Duracell one but issue still occurs. A good friend has now sold me an Ivybridge motherboard (Gigabyte GA-Z77X-UD5H). He only upgraded to move to an M-ATX Ivybridge build. I have moved the 2500K into this motherboard, transferred the RAM and tried with and without the video card. The computer initially turned on but no picture with onboard graphics over DVI. With the video card the computer turned on and displayed the splash screen but never progressed further. After repeating this a few times, it now has the same unfortunate fate... No longer turns on. Motherboard power button is lit up but power button does nothing. Since the motherboard change, it has been set up on top of the motherboard box to prevent shorts inside the case. 

 

RAM - I have tried each stick of RAM in each DIMM slot on both motherboards. Same issue occurs.

 

I have tried to diagnose each part above with and without the SATA drives plugged in (Three SSDs and two HDDs). This leads me to believe that it's actually the CPU which is dead and I am planning to get a used Ivybridge quad core tomorrow unless someone can convince me otherwise. The AX760 has always been powered through a UPS until recently with testing new hardware.

 

Thanks in advance!

 

 

[DragonTamer1]

Have you tried reinstalling your OS after the crash. It's possible that it got corrupted and is unable to boot into windows.

 

I had a similar issue here but it turns out that it's a problem with the power delivery on the MB.

[tincantuna]

I can't boot into the BIOS, let alone reinstall Windows  And this issue is occurring with both motherboards. The Z77 was taken from a working machine too. 

[tincantuna]

Update - now tried an i5 3470s. Same issue. Any help would be most appreciated :'( sunk £100 into this so far

[Quinnbeast]

Hmm, my gut feeling is a flaky GPU - partly because a dead CPU doesn't typically result in intermittent faults. It should also be easier to confirm or rule out. I had issues with an old Nvidia 780 where it would take me 10-20 minutes to get the PC to power back up after a crash, probably relating to some sort of safety trip either on the PSU or the GPU itself.

 

It can be hard to tell exactly what you have and haven't tried in these situations. If it was me, I'd power off the machine (switch it off at the wall) pull the GPU out, pull the CMOS battery out, press the power button a few times and then leave it for 10-15 minutes. After that, try going back to your iGPU... you mentioned getting no output via your onboard graphics, but without BIOS access it's impossible to confirm the settings for the (display) boot device. If you had it set to PEG/PCI, then it's correct that it wouldn't display anything through the iGPU at all. Hopefully, a CMOS reset will put it to auto / default and give you an output. Can you try other cable types if the DVI isn't working? VGA? Display Port etc?

 

If that doesn't work, can you borrow another GPU from somewhere or test your own in another machine (i.e. at your friends place?)