I was using my pc normally this evening, and suddenly the electricity went off and returned in a minute, when I opened my pc again the monitor got no singal, I connected monitor to the build-in gpu of the proseeor it showd signal, I opened the case to check if the gpu is okay, and it was fine I guess, rgb working fans spinning and it seemed normal, i pluged it off cleaned it and re-installed it but the same problem exists, and when I open device manager on windows it detects the internal intel gpu and the external is not detected, it's working but not detected by the pc what may cause the problem ?