Monitor won't receive signal from PC

Hello,
I am looking for advice on how I can solve my monitor from not receiving any signal from a old PC of mine, I'll try and explain what happens so you have a better idea of what's happening.

Firstly, I've setup the PC correctly and all of the cables are firmly and correctly plugged in. VGA cable, Power cord cable, USB Wireless mouse/keyboard adapter)

When I start the PC, there's a beep that lasts 1 to 2 or so seconds and when I look at the monitor while the PC is turning on there doesn't seem to be any error message and the monitor light stays orange.

The PC seems to sound fine but If I remember correctly the last time I used the PC it didn't make a beeping noise when I turned it on, and It's not the monitor as I'm using the same monitor for another computer, but I have also tried a spare monitor and I got the same result. Since the last time I've used this spare PC I have moved houses, and I have taken the casing off to clean the inside of it with a slightly damp cloth.

I hope I've given you enough information to help me and I thank you in advance for helping me with this problem.