Problem With External Mic

Hi,

Im useing Hp Pavilion Dv9000 , recentlly i bought Philips PC Headset SHM1900 for using skype ...when i pluged both the mic and speaker pins in the slot,i can hear music and others but mic not working...i tried all the options in control pannel for sound....should i install any drivers to make the mic work??? please let me know

Thanks...