hello i need help with RX480 8gb nitro..my card was very hot and i take it to replace thermal paste and when i did that i put gpu back in pc and say no signal on monitor...i tryed everything i didn't do nothing just replace paste...and i take gpu to the electrician and he try gpu and say he really don't know what can be issue he say gpu has everything right power fans he try everything and he say he really don't know why gpu won't start like pc don't recognize it ..but card was working when i took it out and replace paste...what can be problem????any help
Try installing the GPU card in another computer. If the exact same thing happens it is possible your GPU card got damaged from overheating or the Cowl (heatsink and fan) cover is not making good contact with the GPU chip.
Use integrated graphics or a cheap GPU card and see if you get video. Got this from this website : Symptoms of a Faulty Graphics Card and How to Fix Them - Make Tech Easier
Try installing a older AMD Driver and see if Windows recognized the GPU Card.