sound input problem

[Henben248]

I'm running JaS 10.4.8 upgraded to 10.4.9 on a Dell Inspiron e1705

 

An internal microphone is detected in system preferences>sound>input

 

but it doesn't work (no sound is detected and shown on the "Input Level" bar, when I talk into the microphone I plugged in)

 

I did read that 10.4.8 doesn't support sound input; is there a solution to this???

 

By the way, my sound output works.