Keyboard Buttons Don't Work

I have an Alienware Aurora which the Dell support page identifies as "Late 2009" (i.e., no model number).  It has a plain keyboard, not a TactX model, with buttons for controlling audio and video playback.  I recently had to reinstall Windows, and since then the a/v buttons don't work.  I presume I need a driver, but the keyboard drivers Dell support offers me are for TactX keyboards, and don't activate the a/v buttons on my keyboard.  Can somebody give me a link to download the proper driver for my keyboard?