Gpu

Hi I have a problem with my pc every time I turn it on the gpu start than it turn off and keep on happening until I turn it of. Also my gpu has worked with the other motherboard that I had before the one I have mention in the spec and it was asus m5a97 le r2.0. 

Spec:

Gigabyte 97A-DS3P AMD 970 motherboard

AMD FX6300 Black Edition 6 core

HyperX 8GB 1333MHz DDR3 CL9 DIMM HyperX black series memort module

Sapphire dual-x radeon r9 270x oc 2gb gddr5 graphics card with boost

Evga 500b 500w bronze power supply

 

Is it the GPU that turns on and off or the whole computer?

Has this computer ever worked before?

It might be your power supply

Its only the gpu and no because I just bought it 

I'm a bit confused.  It would be nice if you gave us a deeper explanation of what happens when you click the power button.

I mean it work with the first motherboard I had and that was a asus m5a97 le r2.0 I changed it to the one I have mentioned in the spec because it had a bug inside bios

As soon I press the power button the gpu fan stops than it starts than stops and keep on doing this until I turn off the computer.

Do the case fans also spin up and spin down, like what the GPU fans do?

No they working fine

This happened to me on my GPU ( sapphire R9 270x OC ed. ) , was according to them a short circuit , I sent it back .

If it's 100% new , send it back , if not , then PSU / lose connector somewhere .