Thanks, sml156! I used the block command and it appears to work. Now Windows automatically connects to "home-wifi" on boot, rather than xfinitywifi.

Thanks again! I appreciate it!

No, not yet. I appreciate the reply and will try it if no one has any other solutions.

I just don't get why this is happening, though. Why would Windows decide it's OK to connect to this? Perhaps...

I feel like you're not reading what I wrote. I do not have Comcast. No service from them AT ALL. No cable. No xfinity. No box. No grey box on my house. Nothing. I have a DSL line from a local ISP...

Sorry, I might not have been clear:

-I do not have Comcast. I own my own WiFi access point. WiFi is on and working. No problems.

-When I boot up, Windows automatically connects to...

I've got a weird problem I can't figure out:

New Surface Book running Windows 10. Every time it boots, it connects to "xfinitywifi" (an open WiFi access point apparently belonging to a neighbor)....