Hello, I don't know how is your computer configuration but try disconnecting all power source (also the PSU from the mother board and GPU ) and try resetting also the motherboard to the default settings (if you made OC). There are some boards that have a reset button, otherwise you might be able to remove the small battery for a couple of seconds (just time enough two empty all the capacitors in the motherboard).
Clean everything!, dust can cause electrostatic shocks that can derive to a malfunction.
It worked for me a couple of times. I hope it also works with you!
Best wishes!