Question Pc powers on then powers off

[Brecony]

Im trying to fix a pc for my friend since their pc died randomly and it got sent to me since it didn't power on at first I thought it was the power supply so I replaced it and since that still didn't work so I replaced the motherboard as well but it still didn't completely power but the motherboard was broken since im now getting a flash of light and and the fans of the graphics Card start up for a second and then stop but I can't think of what else it could be
components:
cpu = intel i5 (I don't know the specifics)
gpu = amd radeon (also dont know the specifics)
power supply = Aerocool Integrator 700W Power Supply, 80 Plus Bronze
motherboard = Gigabyte H310M S2H Intel Micro ATX Socket LGA 1151 Motherboard
ram = 1 stick of 8gb corsair ddr4 ram
hard drive = 1tb seagate
I think the cpu got fried along with the motherboard but I didn't want to buy a new one without confirming its the cpu

 

[rgd1101]

intel i5 (I don't know the specifics)

do how did you know it work with that h310m s2h motherboard?

 

[Brecony]

do how did you know it work with that h310m s2h motherboard?

that was because I took the old motherboard chipset and brought the new motherboard with the same chipset

 

[rgd1101]

if the i5 have igpu test without the amd gpu

 

[Brecony]

if the i5 have igpu test without the amd gpu

after taking the gpu out and powering it on the case fan started up but I didn't get a video output and it stopped after like 2 seconds

 

[rgd1101]

it does sound like the cpu. How did your friend fry the motherboard?

 

[Brecony]

it does sound like the cpu. How did your friend fry the motherboard?

They don't know all I know is that one day it stopped powering on

 

[Brecony]

I have gotten I new cpu (with no onboard graphics) and put it into the motherboard what still didn't work until I took the gpu out where it seemed to bootup(going by the fan activity and how hot the cpu was getting)

 

[ragnarok0274]

The PSU could have fried the mobo and CPU. Aerocool ones are a bit flaky.

 

[Brecony]

The PSU could have fried the mobo and CPU. Aerocool ones are a bit flaky.

we have a new motherboard and cpu and it boots up(I think) but when the gpu is plugged in it doesnt

gpu = gtx 970