You will need to go to the IBM site and lookup downloads for the exact model number of your thinkpad, they have all the drivers listed in a easy layout...dont have to register but you will find what you need under sound/audio driverers in the downloads section of the support page for the model you enter. Laptops usually have third party software from the mfg. that control display and sound.
http://www.ibm.com/support/us/