I have come here to only share my experience. I have fixed this problem but i would like to know what could have been the possible cause for it? So about a month ago i replaced the video card in my PC with another card. I first uninstalled the existing drivers, and then replaced the GPU after having the power cord removed. I did everything correctly but still got No display on monitor error. I tried to reseat the GPU and RAM a few times but no luck. Instead, my PC started to make 5 beeps. Since it's a Dell PC i was almost sure it was a sign of CMOS battery failure so i ordered a 3V CR 2032 battery. Though it has not been long since i had to replace the battery because of the same problem. I just gave up. But then comes the interesting part. In the evening when i turned on the PC, it came back to life again. I have no idea how this happened. Whatever i had to do, i had already did in morning but nothing worked.