Issue with Monitor, I think..

I have a Dell E520.... it's been turned off for almost a year...I'm guessing someone did something to it.... I thought it was the monitor but it works on my other computer..tried using a different monitor but it's not the monitor...... It's Window XP.. I went to turn it on, has a whining noise for some reason.. I can't see the screen at all as it's not recognizing the monitor. I don't know if it could be something else or not.  Was wondering if anyone has had a problem like this. I'm not able to view the desktop without a monitor attached... any suggestions.... Is there any way to view the desktop? Can it be fixed? Is it worth fixing? Thought maybe I could hook it up to my computer but it didn't do any good as I can see the screen and I know my monitor works....

Suggestions would be appreciated..Thank you