Question Beeps but no display

[Andrew297]

When I press the power button, the computer starts and makes a single beep sound(which always does when it boots) but no display. After I unplug it from the wall and plugging it back in it powers on just fine, but Windows instead of using its fast startup feature it does a cold boot(like how it does when you restart it or force shutdown). This happens once 2-3 days. And when I had no display I tried pressing Win+prt sc to take a screenshot, and when I unplugged the PC and plugged it back in i was able to see the screenshot that I took, so clearly the pc boots into windows.
Sorry if this isn’t the right forum

 

[rgd1101]

full system spec? include brand and model of the psu

 

[Andrew297]

mobo: asus p5b-e plus
Cpu: intel core 2 quad Q9650 @3.0GHz
Ram: 8 GB DDR2 800 from Samsung
GPU: GeForce 750 Ti FTW EVGA
PSU: 420W Bower ATX12V P4-EN60950 (PFC)