Question Black screen issue

[username147]

While I was making something in Blender my PC screen randomly went black, then my fans got really loud. So I rebooted it and again only a black screen with loud fans and a single beep from the ASUS motherboard. Everything was lit up and I don't know what the issue is. The GPU wasn't hot and the fans weren't covered in dust. And my CPU is watercooled.
GPU: 1080 gtx ftw2
Motherboard: ASUS Sabertooth Z77
CPU: Im not sure but its an old i7
RAM: 16gb

 

[ConanLock]

Hi, do you know what PSU the system has? If you don't know, there should be a sticker on it that says (will be inside the case, it's the large cube with all the cables if you are unsure). Also, how old is it (roughly)?

Also, according to information I can find about ASUS beep codes on the internet, 1 short beep should mean everything is working. You could check that the monitor is working properly, either by plugging something else into it, or by plugging the PC into a different monitor. Also check that no plugs are loose - the mains power cable and video cable, as well as cables inside the computer (just make sure they aren't loose).

 

[username147]

The PSU is a corsair CX 750M. I replugged in all 3 monitors and there are no loose cables. also the pc was built in late 2013 but the gpu was upgraded last year.

 

[username147]

Also the power supply
was upgraded either this year or last year