There should be a "Network" shortcut on the Start Menu...first menu that opens, right-hand column.
If it's not there, you can add it by right clicking the Start button, go to Properties>Customize button and check "Network."
You can also go to the go to Control Panel>Network and Sharing Center. In that window, I had to turn on "Network discovery" on before it would see any kind of network.
When I open Network and Sharing Center, then click on "View full map," it shows me this computer, the router and the internet. At the bottom it shows the one other computer in the network saying "The following discovered devices cannot be placed on the map" with an icon of the other computer. When I click the icon, it opens the shared folders and drives on the other computer. So don't be surprised if it does something equally illogical for you, too.
