I am somewhat good with computers, and I just bought a custom built PC. It boots on, all fans spinning, lights on, no beeps, but nothing on display. I messaged the person I bought it from, and they said it worked with HDMI the day the shipped it. They have 100 % positive feedback, and tried helping me a bit. They said to make sure the gpu is fully inserted, and that it is plugged in as it might've moved in shipping. I put force to make sure that it was inserted, but it still isn't working. Should I remove the graphics card, put it back in and see if that works?