Set Windows default sound scheme using GPO

We have 50 Windows 7 client computers in an AD OU for which we need to change the Windows Default Sound Scheme to None.

How can this be accomplished using Group Policy?

For domain function level before 2012 go to User > Configuration > Policies > Administrative Templates > Control Panel > Personalization then there is a setting Prevent Changing Sounds.

If you rolled out the desktops without the theme set in advance (as default) then I would use the above GPO in conjunction with enabling the "Load a specific theme" setting (also in the Control Panel > Personalization node of Group Policy). Just make a theme that you want for all users to use then save it somewhere all users will have access to and then put in the UNC under that object.

User Configuration > Preferences > Windows Settings > Registry

Set the following registry key:
HKEY_CURRENT_USER\AppEvents\Schemes
Value: (Default)
Data: .None