Every device in or on your PC needs a 'driver' to make it work and to tell Windows what that device is. A driver is simply a piece of software, but it has to be written specifically for each make/model of device, so you need to know (obviously) the make/model of your soundcard so you know which website to get it's driver from.
If you don't know this vital piece of information, please download and run 'Belarc Advisor' and post it's output to the forum so we can see what make/model your PC is and it's motherboard details. belarc advisor is here:
http://www.belarc.com/free_download.html
No need to install it. Just double-click the downloaded file to get the information about your PC. Send that info to us.