Unfortunately last week my computer that I've recently built stop working at least display wise, and I know it isn't the GPU as the GPU works fine in my backup PC. I'm starting to wonder if it's either the motherboard or the hard drive. Any suggestions on what I should do?
Specs are a good start. In the meantime, check your power connections to the motherboard. ALL need to be plugged in. Same with the video card.
Check the specs of your pc. You need to turn off your computer and try to remove the battery first. Try also to clean your ram but please be careful as it can cause some damage. Try to check if it works.