Go into Control Panel/Device Manager. Find the headset. Right click on it and select uninstall. Follow the prompts.
Then follow the directions on the Corsair site:
Version 1.1 headset drivers are now available for the HS1 and Vengeance 1500 gaming headsets. These drivers are compatible with all Windows operating systems.
IMPORTANT NOTE: Be sure to follow these steps when installing the new driver:
Remove the current Corsair headset driver
Restart Windows
Install the new ver 1.1 driver
Restart Windows.
*PLEASE NOTE THAT YOU WILL LOSE ANY SAVED EQUALIZER PROFILES AS A RESULT OF UPGRADING*
http://www.corsair.com/vengeance-1500-dolby-7-1-usb-gaming-headset.html