To turn on/off the Left Navigation Menu, follow these easy steps:

1. Login to your Administrative Interface
   
2. Click on the "Settings" link.
3. Click on the "Site Design/Layout" tab.
4. Click on the "Edit" link in the section entitled "Design Layout"
5. Change the field entitled "Show Left Menu" to "No" to turn off the Left Navigation Menu or "Yes" to turn on the Left Navigation Menu.
6. Click "Update"