My laptop heatset are not working

Hello,
Sir, i m having Compaq laptop. I m having this weired problem from my headset. it doesn't work when i plug it into my laptop. although the sound is coming perfectly from the speakers. its having windows XP. and i formated my laptop few days back. since the problem started before that it use to work if i mute the laptop speakers.
please help me out please . thank you