Test your new network by connecting to each PC's drives and printers from the other network peers. If you purchased Internet sharing software, try connecting to the Internet and surfing from each PC and notebook.
If the PCs don't recognise each other, double-check the obvious possibilities, such as antenna connections. Also, make sure you really have sharing enabled (reread Step 6). If those steps don't help, go to Start-Settings-Control Panel-System and click the Device Manager tab. If, under Network Adapters, the icon for your new wireless network adapter is shown with an exclamation point next to it, there might be a conflict with another device, preventing the adapter from working properly. Select Start-Help, search for "networks, troubleshooting," and follow the directions.
If the PCs still aren't communicating, it's time to call tech support.