okay this is how its done i have a Compaq Evo n610c Pentium 4 and the way i did it is. first you have to have an internet connection then go to start menu,control panel,hardware and sound then go to sound windows 7 will let you know that you don't have audio drivers and ask for you trouble shoot option and fix the problem and it will automatically find it for you and/or update it for you. here are my specs on audio controller.
Intel(r) 82801 CA/CAM AC'97 Audio Controller Default Device.
Mexican man muy buena suerte con tu computadora