Viewing networked XP computer from Win 10 pro 64 bit

[#1]

Yes, IPV6 can cause issues.

Start at the start: from a command prompt, try "ping <xp's IP address>": you should see a response (use "ipconfig" on XP machine to view its IP)

Try opening a file browser, and connecting to "\\<xp's IP address>\c$" - if you are lucky, you'll be asked for credentials, and you'll see the c:\ listing of the XP machine. If you get that far, then your network and inter-machine connections are fine, it's now "a windows problem" 🙂

[#2]

Is the network set to public or private? Go into the network and sharing centre and it should tell you there.

[#3]

You aren't going to believe this

I haven't changed anything but suddenly it works