Grievouscrib7

You might have unwanted programs running in the background if your cpu has high percentage usage while idling if you haven't already I'd run something like malwarebytes to check for malware. But a cpu overheat seems possible especially since you have a stock cooler. Try running cpu benchmarks and check the temps.

I'm thinking you need to reinstall your graphics driver but I'm not sure how you could since you have no output

Oh try re seating the card then reboot

Download something like gpu-z and make sure that your gpu's usage and thermals are good.

If it is posting (I think that it staying on means it is) then it is probably a gpu problem given that there is no display. Try taking out your gpus first and then use onboard graphics to see if it displays anything. I had this same problem a while ago and that worked for me.

You mean that after reboot it isn't posting or do you mean your not getting an image but it stills posts. If you haven't already I would take out your discrete graphics and try rebooting again.

tablet/phone cpu vs. Desktop cpu