Monitor stuck in power saving?

[Emlxn]

I have an old custom build pc (7-8 years old) which was working perfectly fine yesterday. The pc was being used secondary to my newer pc. When I came to shut down the pc yesterday windows wanted to update so I updated and shut down. This morning when I come to turn the pc on there is no life from the monitor. The monitor I am using for this pc is connected to the gpu via vga to dvi adapter. I have tried another monitor with the same connections and it also does not work and just says entering power saving mode. When I have the monitors plugged in the pc still works as I can hear sound and the mouse and keyboard still light up.
I have also tried connecting the monitors to the on board graphics and no joy.
I have a third monitor (hdmi input into monitor and dvi into gpu) which works however this is the monitor for my primary pc which I need.
I have updated graphics drivers and chipset, however when I tried to update vga drivers it said pc didn’t meet the minimum requirements?(maybe driver is too new for hardware?)
I have tried a multitude of different cables and adapters, I haven’t reseated the gpu yet although I will try this too. Does anyone have an idea of what it could be? Thanks.

[jmarket]

Hi,

Could you provide us with some specs of your PC? It’ll help us tremendously in troubleshooting if we know the hardware

[Emlxn]

Hi, I’m not sure of the specs as it is my boyfriends pc. When connected to the monitor it is showing the a2 boot error code but not when it’s connected to the monitor for the other pc

[Rustys]

a2 boot error code

Usually means that the system does not detect any boot device.
Do you see press F1 any where?

Make sure that they are no other devices connected except the keyboard and mouse and monitor
Different monitors do any work or just still the one?

With the monitor that works is connected.

This does not include the power supply unit we will need the make an model of that.

Download then run Speccy (free) and post the resultant url for us, details here, this will provide us with information about your computer hardware + any software that you have installed that may explain the present issue/s.

To publish a Speccy profile to the Web:

In Speccy, click File, and then click Publish Snapshot.

In the Publish Snapshot dialog box, click Yes to enable Speccy to proceed.

Speccy publishes the profile and displays a second Publish Snapshot. You can open the URL in your default browser, copy it to the clipboard, or close the dialog box.