If you're familiar with laptops, you could take it apart and make sure that all connectors are fully inserted, that the fan stats (if it should), etc. If that doesn't help, then you'll have to decide if it's worth sending it to a laptop repair shop.
all these guys pretend they know and not even 1 answer suggests the problem
I can tell you mate 100% gpu, dont even get a motherboard from ebay because it will die within 3 months, dont have it repaired because it will die in 3 months, I do repair these permanently with reballing.
I`ve read that there seems to be issues with certain HP DV series laptops with an nvidia chip on the motherboard.They overheat and eventually die.There are bios updates on the HP website to adjust the system fan speeds but i`d guess it`s too late for yourself.