all of a sudden this very high pitched noise came in my room, and only my room.

 

When i turn off my computer screen, it stops, when i turn it back on, it goes on again.

 

any idea!?

turned off the comp, and now it doesnt do it anymore,

 

but anyone have an idea why it did?

Well are there speakers in the screen?

 

Is it flat screen? CRT?

 

How old is it?

 

When did you last hit it with a baseball bat? (not recommended!)

there are no speakers in the screen.

 

its not a flat screen.

 

its actually pretty old, like 7+ years old.

A 7 year old screen making funny noises.... well I don't know but it sounds like the monitor is dying.

 

A monitor that old will die sooner or later and I have seen monitors die, the one I saw kinda made a low buzzing noise, but there are many things which can go wrong in electrical equipment like monitors.

 

How loud was the noise?

 

Try switching the monitor on now without the computer input (so it'd just display a black screen), if it still is making the noise then clearly merely having power in it is causing a problem.

The most common problem with old electronics is failing electrolytic capacitors.

well, it stopped now.

 

it wasnt really a buzzing noise, just a constant high pitch.

 

the noise wasnt that loud, you had to be sitting in front of it to get the full feel of it, if i stood 10 feet away, i could barely hear it.

 

and i turned off the comp, and left the screen on, and it didnt make the noise

That happened to me whenever I played Il-2 Sturmovik on my computer. It fixed itself after a while.

the flyback transformer inside the monitor runs at several kilohertz, on occasion this sound can be heard as a high pitched whistle. it`s nothing to worry about

The pitch of the sound will often change, appear and disappear according to what is displaying on the screen. If it becomes annoying you can just change the refresh rate to get rid of it.