Download & install Audacity. When prompted, click "save" and save it to your hard drive.
After Audacity is installed, close it and install the lame_enc.dll installer. Again, click "save" when prompted, and save it to your hard drive.

How do I configure Audacity to export as mp3 files?

Open Audacity
Open the Audacity Test File (watch tutorial):
Click the "file" menu (found in upper left hand portion of your screen)
Click "Open..." and type the following:

(You may copy & paste it if you wish)
Click "Open"
Export the Audacity Test File:
Again, click the "file" menu
Click "Export as MP3"
You will be prompted to save your the test file. Save it to your hard drive where you can easily find it.
Click "Save"
You should now see the following window:
Click "yes"
Type the following C:\Program Files\Audacity\Lame\lame_enc.dll

(Again, you may copy & paste it if you wish)
Click "open"
You should now see the following window:
If you want to edit the ID3 tag, may may do so, but it is not required.
Click "ok"
Audacity is now configured to export mp3 files. You should not have to repeat this process again.

The microphone won't record