FYI, you can set this in your environment variables and it will always be enabled when you go to the device manager. For Win 7:
- Right click "My Computer" and select "Properties".
- Click "Advanced System Settings" on the left.
- Click the "Environment Variables" button at the bottom of the "Advanced" tab.
- Create a new "User Variable" to add it for just the current user or "System Variable" for all users.
The setting takes effect immediately on Windows 7, not sure about Vista.