I did some more digging, and apparently Windows doesn't delete the TCP/IP port when you remove a printer in Settings. There are various instructions on-line on how to delete an unused port. Sometimes you can do it from Settings, but often you have to stop the print spooler in Services and then go into the registry to get rid of it.
We have 3 identical laptops. We used to print over a wireless network just fine with a Versalink B600 printer, but it died. We now have a B400. Initially, there was something off in the way it was set up on the network, and I couldn't get it to work. Our IT department fixed the network issues, but somehow the driver installation on the computer I used as a guinea pig got corrupted. The Xerox app can find and communicate with the printer, but it won't print. Windows trouble-shooter seems to think there is a network error. Before deciding there was a network issue, I first tried installing the printer from Winows using the the printer IP address, becaseu it couldn't find the printer by name. When that didn't work, I downloaded the Xerox app and tried installing with that, again using the IP address.
On the other two machines, I uninstalled the old printer, downloaded and installed the B400 software app, and both of those are working fine. One difference is that I told the app to find the printer by name, rather than by IP address. With the network issues fixed, the app had no trouble finding the rpinter by name.
I then went back to the first computer. I have deleted the printer, uninstalled all the Xerox software I can find, cleared the print queue, etc. and then re-booted. When I try to do a clean install the way I did on the other two machines, it says "Oh, it's already here", and duplicates/re-uses the faulty installation using the IP address.
My suspricion is that the uninstall process is leaving registry entries behind. I will try to clean the registry the next time I battle with it. I have very limited access during the summer, and it's in an area with no air conditioning. I can only work on it one or two mornings a week, and then only before it gets too hot.
Any other suggestions or ideas?