My display cuts out randomly and won't come back till a restart

[RandomUser123]

I recently upgraded my graphics card to a GTX 980 and everything it need like power supply and a bigger pc case.
I have had the system for a week and a half playing fairly intensive games like Bf1 with no problems except a scratchy sound while booting. This morning I went to turn it on and it wouldn't go past post. So I opened my case, discharged myself and pushed everything in to make sure it was fully seated.
A couple hours later my screen cut out and my monitor gave a message "Hdmi no signal" but I could still hear the game audio.
I left it a couple of hours and tried again. It got through to my desktop before the same thing happened.
Now I am lucky to get to bios.
Any suggestions?

 

[RandomUser123]

Update think it might be my graphics card because taking it out and putting it in allows my pc to work normally without any strain on my gpu ie no games. But it survived 30mins before cutting out just watching yt. My gpu is also not currently screwed in but idk.

 

[RandomUser123]

SOLVED mostly. I know what the problem is. Because of the weight of the graphics card it is pulling it out but because there is no holes it is a temp solution.

 

[Quantum_5]

I've had a 980 for about a year now and i get the same but only when i try an overclock, played bf1 fine but i tried an overclock again and same thing happened. I was thinking i need to upgrade power supply, what did you buy?