No audio when inserting using headphones.

Hi ,

I have a Dell Inspiron N3010 laptop running Windows7.

Audio works just fine with the speakers, however when I insert the headphone jack I hear no sound with the headphone. (The speakers do mute as expected.)

I tried 3 different headphones, I don't believe the  problem is with them.

Does anyone know how to fix this issue? 

Tzachi