Start -> Control Panel -> System -> Hardware -> Device Manager. Click on the + Next to sound video and game controllers. There should be a list of them, one mainly being your soundcard. Right Click on them one at a time and select uninstall. Once all removed restart your computer. Each of those removed devices should plug and play upon loading windows desktop. If the soundcard does not install, then I would go with updating the driver, providing of course you know what it is.