When u formated your system PC u lost your sound driver.
Download the sound driver for your laptop and install it.
Fair enough. @ poster can you please check Volume is turned up and not muted. also next time please try and specify if you"re on Vista or XP.
Try gettting to device manager to verify if you have sound drive installed. for infor on getting to device manager try googling it and you"ll see step by
step infor on how to verify that. since we dont know whether is XP or Vista it wont be prefessional of me asking you to downnload drivers. Good luck