Computer no longer displaying video on monitor

Hello everyone! This is my first time posting although I have been a regular to this website when in need of advice. I built my very first computer last night and everything seemed to work just fine. I was to the point where I was installing programs onto it. I got tired and went to sleep. I woke up to find that the computer was on, but it didn't have a display on the monitor. I kept trying to find a source on the monitor, but it just wouldn't. Everything in the case seems to be working just fine, all fans are spinning. Does anyone have any idea what is happening? As my first build, I'm a bit worried something has gone awry. Anything would be appreciated. Thank you.

System Specs please?

Have you tried rebooting and go to the BIOS?

Well something maybe has happened through your sleep, are you sure everything is fine? Try another GPU?

It sounds like an issue with our power supply. Are you sure all power connectors are in. one might has slipped out.

Ok try to pull video card and memories out and turn comp on. DO you hear any beeps?

The computer turns on, but nothing really boots. A friend and I tried my GPU and ram on another motherboard and they worked fine. We tried some spare parts he had on mine and we got the same results I kept getting. I can't turn the system off via the power switch either. Sorry it took me so long to reply. Also, I never heard any beeps. I don't think my motherboard has an onboard speaker though.