Please check in your volume control (alsa mixer) that under Options tab, the "Digital Mic" is showing under digital Input source, and then Input source "Mic" is showing. (Front mic would be for the external plug-in mic).
Then make sure that under Recording tab the mic slider is not muted. Just right click to un-mute.
If you still don't have the internal mic working, go to the Switches tab and select or unselect Analog Loopback.
The Preferences button should make any of these tabs/selections available if they are not present in your alsa mixer.
Malachi 3:10 NRSV
...says the LORD of hosts... I will not open...windows...for you...
Linux user since 2001 pda; 2006 lappy