Hey, piccolo,
sounds like the monitor is dying a slow and painful death---
it is emitting what is known as the monitor whistle of death.
Is it still under waranty, or just an old one from the garage?
You can still use it, but if you smell anything funny, or a change in pitch, then either kill the power to it, or run for your life, for the fire extinguisher
Seriously, though. be careful, and try to get it replaced. I had an old monitor that started doing that, and then the lines of pixels began to jump left and right for more than an inch! (That's when I decides to get a new one.)
Do you hear any crackling noises when it powers up?
What brand is it?
(PM or ICQ me please -323115115 )
Uniacke1