Updating a driver
"Icons" views have a direct link to Device Manager, as does "Classic View" on Windows Vista only.
Then expand "Sound, Video and Game Controllers" by clicking on the sign, right-click over the sound device and click "update driver".
If rolling back does not help or makes matters worse, go back to the "Driver" tab and click "Update Driver". If the driver provider is now Microsoft you could see if your problem is resolved, but the general recommendation would be to visit the website of the computer or motherboard manufacturer and look for appropriate drivers specific to your computer model and version of Windows.
You may need to find out the name, specifications and current driver details for your sound device, so you can update it correctly.You can search Google or Yahoo to find the correct internet address of the manufacturer.If you have a branded computer, go to the computer manufacturer's website.If you are reading this because recordings have always worked fine in the past but are now recording incorrectly, or because an input is missing or Audacity is no longer launching properly, an automatic update via Windows Update may just possibly have caused the problem.Windows Update is potentially less reliable about obtaining appropriate hardware updates than Windows Device Manager.