Inspiron N5040/Windows 7 - High Pitched "Alien type" of noise. Internal Mic problem

I don't know if this problem has been addressed to date.  Please forgive me if it has, but after searching for an hour now, I haven't been able to find the exact problem.

I have a Inspiron N5040-9252/Windows 7, purchased in July 2011.

Since August 2011, I have had a very high pitched "Alien type" of squealing/knocking noise that starts every time I turn on the laptop.    I have learned to mute it with the Fn and Mute button.

Then I must go into the mixer on the speakers and unmute all sound and then mute only the Inter Mic IDT High Definition.

I really could care less if the microphone works, but needless to say, the microphone SCREAMS if I attempt to unmute it and communicate via Skype.  The webcam works, but I can't use the microphone.

Is it the sound card? 

Does anyone else have a similar problem?  If any of you have a possible solution, I would really appreciate some help on this one.  I don't want to loose my computer (to send to repair) for something that might just need an update!

Thanks in advance!