The behavior of Ad-Hoc WiFi in Windows 7:
In order to be able to share your internet connection via WiFi you must create the Ad-Hoc connection from a User account with administrator privileges. Only then you get the "Turn On Internet Connection Sharing" Option towards the end.
In order to be able to share files - you must use a secure WiFi connection and not 'No Authentication' i.e. Open with WEP. Only then will you be able to change the Network to a Private/Home network from Public Network.
In order to be able to share your internet connection via WiFi you must create the Ad-Hoc connection from a User account with administrator privileges. Only then you get the "Turn On Internet Connection Sharing" Option towards the end.
In order to be able to share files - you must use a secure WiFi connection and not 'No Authentication' i.e. Open with WEP. Only then will you be able to change the Network to a Private/Home network from Public Network.