Windows 10 computers cannot see each other on network

I have a network with 3 Windows 10 computers and one Windows 7 computer.  I can see only the Windows 7 computer on my Windows 10 computer.  I have turned on Network Discovery and file and printer sharing on all computers.  I have set Full Trust in Norton 360 Network Settings.  I have Allowed the programs I need to communicate with each other in Program Control.  Its odd that sometimes when I start my computers they can see each other and share files, other times they cannot.  Its random.

Hello Jerry. Wondering if you have the sharing settings set AND the correct network selected in Home networking connection as shown below? The screenshot shows WiFi but can also be selected with a wired ethernet adapter settings.

Sharing2.png

SA