Sorry for delay in replying. Okay, I have put everything back and it is still not working. So, I will try and borrow another monitor from someone, and also a power cable.
In terms of the existing monitor, I do have it plugged into my laptop and it seems to work okay. When it is plugged into the Dell (via a VGA Cable) I turn on the monitor and for a few seconds the green monitor light comes on but then goes to a yellow light which I am guessing is the setting when there is no feed coming into the monitor from the computer.
It may take me a few days to get my hands on another monitor and cable. Please wait.