Help with Monitor, Please

[Illusiphix]

Ok Just to start I'm new and I don't know if I'm posting in the right place so If I have bear with me.

I turned my computer on (after removing the VGA(The Darker Blue One lol) for use in another computer) and I turned it on to boot-up and my monitor stays in Stand-by, when I removing the VGA it displays the "No Signal" warning. I turned it off (5 second button hold, which pains me to do) I left it alone for a day or two to check if it wasn't just a one off.

I haven't opened my computer to check if there is anything wrong yet I wanted to ask for suggestions (I'm used to being told what to do being an Student ICT Practitioner, which is also annoying as almost the same thing is happening to a friends computer aswell and he wants me to try and fix it).

Please get back to me as soon as you can I am in dire need of software on my main computer for work.

Illusiphix

P.S. if it helps my screen is an old IBM CRT and it does work with other computers

 

[Illusiphix]

Ok I'm posting again to say that I've made an amateur mistake but that still leaves the second problem. The other computer has not been moved yet the user is somewhat Not-in-the-know they encountered a problem that froze their Computer and they turned it off by the plug (wall, mains, socket)

They said it worked for a while after ward but followed almost the same pattern as problem computer 1. I myself turned on their monitor checked all the cables and then turned their computer on... to no prevail. The monitor exclaims "No Signal" then after about 10 seconds shuts off. Cable from and to are in securely. What could this possibly be?

I haven't been able to get behind the computer and have a look as the person keeps it next to a cabinet (about 10cm away) so the cables travel behind the cabinet and has no slack.