I just installed Audacity and Lame. My purpose is to do rough recordings of my band. I did a test recording using my voice and the built in mic of my laptop–it worked fine. Then I tried it on another day and my voice did not show as an input signal and obviously nothing was heard on playback. It worked once so there must be something that is turned off–I checked the audacity mic icon and it is in the middle of the range.
I have a Lenovo laptop–only a year old --good machine.
There is another trick. Open Audacity and click once inside the red recording meters. After a pause, they will wake up and meter the Audacity input making troubleshooting a lot easier. You don’t have to go into record.
It will be, (unless by some weird coincidence you have exactly the same sound card as me).
What you do next depends on a lot of things including; which version of Windows you are using, what sound card you have, what options are available in the Device Toolbar on your computer, what you are trying to record from (which I think you said was to be the built-in mic?)