1. Control Panel-> Network Connections,
2. right-click the connection you want to share (the high speed internet connection) -> properties
3. On the ADVANCE TAB, select the ALLOWOTHER NETWORK USERS TO CONNECT THROUGH THIS COMPUTER'S INTERNET CONNECTION check box
4.Under Internet Connection Sharing, in Home networking connection, select any adapter that connects the computer sharing its Internet connection to the other computers on your network. The Home networking connection is only present when two or more network adapters are installed on the computer
Good luck!