Because you use the same IP for both computers which is not what you should do ..if you want to have a serverand a client or a simple peer to peer network and you connect both computer togheter.
you will also need
a working dial-up Internet account with an Internet Service Provider (ISP) or
b working broadband (cable, DSL, satellite, etc.) Internet connection.
and then :
Click Start, and then click Control Panel.
Click Network and Internet Connections.
Click Network Connections.
Right-click the connection that you use to connect to the Internet. For example, if you connect to the Internet by using a modem, right-click the connection that you want under Dial-up.
Click Properties.
Click the Advanced tab.
Under Internet Connection Sharing, select the Allow other network users to connect through this computer's Internet connection check box.
If you are sharing a dial-up Internet connection, select the Establish a dial-up connection whenever a computer on my network attempts to access the Internet check box if you want to permit your computer to automatically connect to the Internet.
Click OK. You receive the following message:
When Internet Connection Sharing is enabled, your LAN adapter will be set to use IP
address 192.168.0.1. Your computer may lose connectivity with other computers on
your network. If these other computers have static IP addresses, it is a good idea to set them
to obtain their IP addresses automatically. Are you sure you want to enable Internet
Connection Sharing?
Click Yes
if that ain't work i'm sorry that's what my teacher tought me>