I had my PC for 8 years now. I was normally on my PC playing video games when suddenly monitor screen went black and it kept on refreshing (no signal -> black screen -> no signal) every 5 sec. When I restarted my PC it didn't load BIOS, so I flip the switch of power supply and turned it on again. When it loaded MOBO logo it had dots all over it (it looked like it was broken picture), then when text should appear after it I got same symbols written everywhere (instead of text). When OS was up resolution was so low and when I got in Device Manager in Display Device my GPU had yellow triangle. When I was cleaning my GPU (from dust and replacing my thermal paste) the problem solved itself, and after 2-3 hours it's back again.