Sound won;t work

ohkay hello everyone ...acTUAlly i am here asking a question whose answer i have been finding. I have a laptop and got xp installed in it... MY sound in my lappy used to work untill i reboot my whole system and installed windows again.. NOw even after installing sound driver from its cd. the sound thing doesnt come in the task tray pane and hence the sound wont work even i install the driver 100 times. and my sound device wont show in the control panel sound hardware........ i really need some help!...so is my sound card messed up ??? or something wrong with the window coz i have installed the window like 3 times after tht and it still wont work!