Question PC powers on and then off after 2-3 seconds

[Mailo76]

I thought this was an issue with my power supply so I bought a new PSU (RM 850x) and this is still happening. I also considered it might be due to overheating so I installed the H115i and it still seems to happen. Yesterday after installing the new components it happened again but the 2nd or 3rd time I powered my pc on it turned on and I had almost no issues when using it for multiple hours. I also checked my temperatures while using it and everything was within normal range.
I also tried removing the 4 ram sticks and using 1 in different slots but nothing seemed to help.
The GPU is the ROG Strix GeForce GTX 1070 and the motherboard is Asus LGA 1151 Strix Z270 ATX. The CPU is i7-7700K .
I'd also like to note that once I use the power button and it turns off I can't use the power button again until I turn off the back PSU power switch and wait a couple seconds.
Any help would be greatly appreciated.

 

[Ralston18]

Power down, unplug, open the case.

Clean out dust and debris.

Double check by sight and feel that all cards, cables, connectors, RAM, and jumpers are fully and firmly in place.

Try a new CMOS battery.

Look in Reliability History and Event Viewer for error codes, warnings, and even informational events that correspond with the times of the problems.

Go into BIOS and change the POST settings to be a verbose as possible meaning that the system displays what is happening during power up and allows you time to read the displayed information.

Once the problem is identified and resolved you can always go back to a faster POST configuration.

 

[Mailo76]

I cleaned it out again and everything is firmly in place. I also put in a new CMOS battery but that did not change anything. I can't get into BIOS as it just powers off after 2 seconds. Do you have any other suggestions as to what I could do?

 

[thefxgamingrules]

I have faced this issue a few times, all times it had something to do with the CPU. Try reseating your cpu. Make sure all contacts are clean and not damaged; check for bent pins. Remove th EPS power cable for the CPU. If the PC doesn't shut off immediately, it most probably is the CPU.
Also try reseating your memory, and trying them individually. If nothing changes, try using a memory module you are sure that works.
EDIT: Did not notice you had tried reseating memory sticks already.

 

[Mailo76]

I tried reseating the CPU it all looked good underneath and no damage at all. Removing the EPS power cable for the CPU made no difference. It still just turned off after a couple seconds. I also tried reseating the memory again and there was no change. I did however notice that after powering on and all the fans start running that there is a slight click in the new PSU and it powers off. I believe it was the same with the old PSU as well.

 

[Mailo76]

UPDATE: After a couple minutes it decided to start turning on again but I immediately noticed that there was no signal towards the monitors. I also noticed that the fan in the PSU was spinning but slowly stopped while all other components were running.

 

[thefxgamingrules]

Try removing the GPU and see if you can get output from the iGPU.

 

[thefxgamingrules]

You have another PC to test the PSU in?

 

[Mailo76]

I've tried it with 2 different PSU's and both have the same issue however I rewired everything 2 days ago and my PC started to turn on but was showing an issue with the RAM. I removed the last stick and my PC started to work normally but the next morning I once again run into the issue of turning on the PC and it shuts down after 3 seconds.