I'm trying to set up a LAN among four computers, 3 of them Win 10 and one Win 7. I believe I have everything configured correctly per the manual, although two of them (the Win 7 and the oldest Win 10 - which itself used to be Win 7) were once on a homegroup whose password I can't find.
For now, though, I just want to focus on the problem of having them see each other, which they sometimes have been able to do and sometimes not. At present, the Win 10 laptop sees only itself when one double-clicks the Network icon on the desktop. The newest Win10 sees only the Win10 laptop and does not list itself. Both PCs are turned on and awake.
Currently the Win 10 laptop is connected via Wi-fi and the Win10 desktop is connected via ethernet. I have just set a network bridge between them. But that did not fix the problem. All these PCs are connected to the same router.

