IT Help (Please!)

Bit of a strange one that I've let go on for a while tbh out of pure laziness...

I usually switch my PC to standby rather than a complete shutdown. When I switch it back on I am greeted by my manufacturers default screen saver (floaty Acer sign) and then manufacturer message ('No signal'). This happens approx 1/5 times.

No matter what I do/press I don't get to where I need to be. The tower appears to be running normally, but the signal isn't getting through to the monitor. I'll usually press and hold the on/off button for 10 seconds. This usually shuts it down but sometimes although its shutdown, I can still hear it whirring away (despite all lights etc being off). The only way of rectifying and getting back to a normal start is to disconnect the power cable at the back.

On reboot I'm met by 'The Bluescreen' notifying me off serious disk error. It tells me its my graphics driver (Nvidia something or other) and I should update it. I have done this but this incident keeps recurring.

My firewall/AV/malware/anit-spy is updated all the time.

Any ideas of what is going on here?