Monitor Problem

Hi, I have a strange problem that I could not find any information on through a Google Search.

Today, I turn on my computer and power on the monitor. The monitor's light turns green, but then it makes the sound that it is turning off, the light changes to orange, but then it turns back to green. No picture comes up at all, and it repeats the on-off process. It is very frustrating- any help? I own a Dell computer that is about 3 years old.

 

Thanks a lot, I think I will just try to use a new monitor, since a relative has a spare one that he is not using anymore.

 

Ok, everything is all good now- got a new monitor and its all hooked up. BUT, not without problems. I set up the new monitor, but again it turned on, and shut off... but this time it just shut off, and did not turn back to green. So, we decided to just unplug everything from the surge and replug everything back in. This time, everything turned on. But there was a message on screen, saying something along the lines of "... the system has unsuccessfully tried to (re?)boot..." I don't remember much of it. Could this be because I was constantly turning the computer on and then holding the button down to force it to shut down?