I have never run any wizard to set up networking - I actually think some of the options are confusing and, if you don't know what you're doing, it is too easy to make an incorrect selection. Also, you *DON'T* need to use a USB key or anything else to transfer settings between computers.
In Vista's "Network and Sharing Center", make sure you've switched "On":
- Network Discovery
- File Sharing
- Public Folder Sharing
- Printer Sharing (if sharing a printer connected to the Vista PC)
Then, ensure that both computers are in the same Workgroup, set any folders that you want to have available over the network as "shared" by right clicking and selecting the Sharing & Security option (XP) or Share option (Vista). Ensure any firewall software is configured to allow access to the networked computers, which may involve adding their IP addresses in a "trusted" section.
That basically should be it, although it might help if you install the Link Layer Topology Discovery (LLTD) Responder from Microsoft's website in the XP PC click here