Solutions:
1.
Make sure all your psu cables are plugged in correctly i ran into a person the other day who hadnt done that and they were having major issues.
2. Try replacing the video cable between your graphics card and monitor. Might have a dud cable.
3.
Try a different monitor. Might have a dud monitor
If these three don't work more serious action has to be taken.
4. Pull out your graphics card and try running video from your motherboard's output this is to check for a dud graphics card.
5. Try a new motherboard
6. Try a new CPU
Basically trouble shoot each component of your computer to find the issue
good luck hope this helped holler if you need anything
ps dud = doa ( dead on arrival)