unable to disable internal mic

Hi, I have a Dell Inspiron N7010 using a Windows 7 OS.

Here's the thing,

Since I got the computer I downloaded Skype and  used the internal Microphone. When I bought a headset about a year ago everything worked fine up until a few months ago. Now when I turn on my computer, I get this awful feedback noise like the mic is right beside the speakers. But it is not. I am using the built in speakers as well. Now a while ago I had this same issue, I disabled the internal mic and had no problems. I turned it back on a few days ago and the feedback noise returned. I tried disabling the mic and it still gives me the noise. I disabled the speakers even, and am still getting the noise. I don't understand. I have restarted the computer and disabled, and enabled many things in regards to sound and still nothing works. I have noticed that when I am on a call on skype, even though it is set to my headset's microphone, I can still hear things through the internal microphone. Also the feedback noise cuts in and out. It will be on for about 10 or 20 minutes at a time, and cut out for about a minute and start again. It squeals louder when I place my hands over the key board.

There is nothing near the computer. It is sitting on a wooden desk like it always has even before I originally disabled the internal mic. I am wearing no jewelry nor have any metal pins or implants on my body. There is no cellphone or anything near the computer either.

So what I would like to do is delete the internal microphone driver. Just get it done and over with. I do not know which driver it is. I accidentally disabled the speakers driver and that obviously made the noise quit but I would still like to use the built in speakers.  I reenabled the speaker driver and the noise returned. It is a terrible sound, and won't go away even if I try to play music.

Someone, please help!