Here's what to do buddy
1; Open up the control panel through your start bar.
2: Double click on 'system'.
3; Click on the 'hardware' tab.
4; Now click on 'device manager'.....You should then be presented with a full list of your computers devices.
5; About two thirds down the list you will see 'sound, video & game controllers'...It should have a yellow question mark next to it (indicating a problem).
6; Open up the sound tab i just descibed and it should be obvious where your problem device is.
7; Right click over the problem device then left click on 'properties'.
8; You then need to click on the 'driver' tab where you will be able to 'update' the driver for the sound card.
Hopefully that should sort you out..........Good luck buddy !!