My ancient Nvidia GPU stops working if the PC loses power long enough for the capacitors in the PSU to lose their stored electricity. It is a total hassle to get it working again because I have to remove the GPU card, remove the RAM, remove the BIOS battery, connect a VGA cable to the onboard GPU... then power on the PC, turn it back off again, re-insert the BIOS battery, RAM and GPU card, plug in the HDMI again, disconnect the VGA cord, then set the internal time again, make any other BIOS changes and boom it all works again.