I am assuming you have been in Device Manager and there is a red X or a yellow Question Mark, noting the lack of a driver.
If you right click the object and choose Update Driver (or Install Driver), you should be able to allow your computer to search the internet for the best driver.
Here is a link to the Realtek page. You can use their drivers as well but it may not have some of the special features the motheboard MFG inserted.http://www.realtek.com.tw/Downloads/downlo...p;GetDown=false
Alternatively, you can install a PCI card such as a Soundblaster, at a minimal expense.