The integrated sound system is often still referred to as a sound card.
For Blizzard games, it is important to download and install all software updates, as our games are designed for the latest version of the supported system requirements.
See Apple's OS X: Updating OS X and Mac App Store app page for Software Update instructions.
During technical troubleshooting, you may be required to reinstall an OS update or driver.
Install the new driver for your sound card if the driver package did not install itself automatically.
If you are using Microsoft Windows XP, click the "Start" button, then "Control Panel" and open the "System" icon in the Control Panel.