The PC stopped seeing the video card, what should I do?

Question

Iron

I came back from vacation, turned on the old PC and calmly surfed it all day. But the next day the PC stopped displaying the image, moreover, all the coolers are spinning.
On the motherboard (asus p7h55), the pci express light is on (it also lights up if you turn on the PC without a video card). Video card geforce 760

I put another video card - everything is fine (it was, now it artifacts (and it’s very strange, usually, artifacts start when I start a very old game, but at the same time, in fullmark it can work for 10 minutes and everything is ok. I guess that’s the reason at her age (gtx460))).

What could be the reason that mp does not see 760? Yesterday I tried to run it again and there was an image (it came to loading windows), but then again, a black screen and a pci express light ... Burned out ?

Ps I cleaned the contacts of both the video card and the RAM - it did not help