My pc is acting strange!

[k3nzo]

Hello , lately i am having a problem with my pc, it wont start unless i remove the psu power cable and after 5-10 sec works but when im trying to shut it down it restarts!I can only shut it down by the power button!First i thought is the psu but after changing it its still the same, i think it might be the motherboard!
Ty for your answers!
Cpu-i7-4770K
Motherboard-gigabyte b85m-d3h
Gpu-GIGABYTE GeForce GTX 1070 Windforce OC 8Gb
Psu-Njoy storm 550w
Ram-8gb ddr3 Corsair Vengeance

 

[cin19]

How about remove the gtx1070, use the onboard iGPU to boot the PC, if the PC will work fine with the onboard iGPU, and you will know the problem is from either the PSU or the gtx1070.

Also if you can use the PC, test the RAM with MemTest86 https://www.memtest86.com/download.htm

 

[k3nzo]

Its not the psu because i had a corsair cx450m with wich did exactly the same and i doubt its the gpu! thx for the fast answer , have a nice day!