Set up file sharing home network with win 10 and win 7 computers

I just upgraded my main computer to 1803 and now most of my network won't connect to each other. I have two computers on Win 10 ver 1803 and two son Win7 sp2. I can't get them to connect. they did for a while and then stopped. I have spent two days reading and checking and can't find out what seems to be the issue. One of the Win7 computers WAS connected, but today, nothing.
Any ideas? I have viewed the videos and followed the online directions and all seems to be set as it should be, but no connection.

I keep getting a dialog box that says "Enter Network Credentials" . that stops me dead.
CPeter

How are you connecting ie explorer or cmd line have you setup shares and set them to everyone. You also need to set up NTFS perimission on the shared folder. I assume your using workgroups NOT home groups as thats now gone.

When you connect there is an option to connect as a user enter a admin username and password there for the pc your connecting to

"How are you connecting ie explorer (This) or cmd line have you setup shares and set them to everyone. You also need to set up NTFS perimission(don't Understand) on the shared folder. I assume your using workgroups(Yes) NOT home groups as thats now gone."


What about the Win 7 computers

NTFS is the same on 7, 8 ,10 Setting NTFS Permissions