Audio device problems..

Hello,
my grandparents computer wasnt working properly so i decided to go and UNINSTALL some things that were rarely used and in the process deleted their audio all together..dumb< yes i know but it was an accident. ive scanned the drivers and found the multimedia audio device needed to be re-installed but the only websites i find to do this i have to register and pay alot of money and i dont want to do that so is there any way i can download this driver for free..i need some help asap and any is much appriciated. thank you