Acer laptop subwoofer noise with windows 7

I recently bought an Acer Aspire 7738G laptop with Windows 7. After a day or two the speakers (in fact i think it was the internal subwoofer) started to make a loud grinding noise which was intermittant but which became increasingly prevalent. It seemed sometimes to be brought on by my going online or somethin like that whilst music was playing, but sometimes started on it's own. Thinking it was a hardware problem I changed my laptop for exactly the same model. Unfortunately however after a few days exactly the same thing has started to happen.

I don't think I am the only one to have had this problem (see link below) and I wonder if it's aproblem with Windows 7 and Acer internal subwoofers. I am not a techy and all I can think to do is to take this laptop back and get a non Acer one. I'd rather not go through all that again (transferring itunes alone is a pain let alone getting the computer to perform in the shop).

Please let me know therefore if there is a simple fix to save me the trouble.

Yea a lot of us acer users have had this although the latest drivers seem to have repaired most of it so if you havent got the lastest realtek drivers i would head over there and get them latest is 2.37 i believe, also take a read through this thread Realtek, Windows 7 64RTM Crackle/static/popping good luck.