Please follow the guide below to create an account for the adults with no restrictions on it:

Right-click on the Net Nanny icon and go to "Net Nanny Settings". Enter your password when prompted. Go to User Settings => Manage Users => Add User tab. Select one of the available icons, and create a user name and password for it. Then click on "add". The icon will appear on the left. Click on it.

Set the blocking level to level 1 (no restrictions). Then go to the "Filtering" tab. Choose the option to "Disable filtering of objectionable words and phrases".

This way, the adults can just log on to this account when they want to use the Internet. Just remember to log off when you are finished.