Acer Aspire 8920G Making Annoying Sound

Hi Guys,
I have my second Acer Aspire Gemstone Blue 8920G in as many weeks. I sent the first one back after taking it out of the box to discover it emitting an annoying high pitch sound.
after phoning the Acer Tech Support they informed me there was a problem with the Screen Globe and to send it back.
Acer quickly replaced it with a new one but the replacement is nearly as bad as the first notebook.
I now have a new replacement emitting the same sound. when you turn the screen off it goes away and when you vary the brightness the pitch of annoying tone varies along with it.

has anyone else out there had similar experiences with their acer gemstones????
im thinking about sending this one back and just getting my money back and going with a whole different manufacture.

 

Do not cross post on these forums please, it is against the forum rules.

 

apoliges, new at this. made the 1st post and could not find it so i thought it didnt work and made a 2nd post. you can delete the 1st post if you like. i would if i could find it.