You should use one of your Windows 7 computers as a host computer for your router and then build your network from it. Windows 7 will configure the network for you in the Network and Sharing Center. Make sure that you change the XP computer to WorkGroup in the System settings. The correct way to load the adapters is to load the drivers first before you connect the adapter and the computer will recognise it. I run a desktop host and use wireless connections on the other 3 laptops 2 have Windows 7 and 1 has Vista. You will need to load each of the computers that have the usb adapters individually before you start to build your network. Once you have done this all the computers should talk to each other.