Problem update (Patreon)

So like a fool i bought a new graphic card, and an other nvida one, a 1060. But it seems when the gtx 770 already made the pc boot slow (adding a 1 minute black screen), this one won't boot at all, mostly cause my motherboard has an outdated bios, but i don't really want to flash it cause i'm not sure what to do exactly... 

For now i'm using my motherboard graphic card and back to 1920x1080, but i can work at least. I'm not sure what to do next. To buy a new pc entirely (without graphic card obviously) or something.