New Windows 10 Pro PC can't access other PCs in workgroup

My home office network was all Windows 7 until last month when I started replacing PCs with Windows 10 ones.

I utilize a NAS server and several external USB boxes to run backups over the network (not Homegroup).

None of the Windows 10 PCs can 'see' the others or the NAS on the network.

However, the one Windows 7 PC left can access the Windows 10 ones.

The answer must be simple as it is common to all my Windows 10 PC's.

When I try to access the Network from Explorer I get the '0x80070035 Path not found' error message.

I have enabled SMB and changed more settings than I can remember and am totally out of ideas. Discovery and file sharing is turned on. Adapters are set to private. What am I missing?

Try to ping other PCs by IP address. If you can see them, that means WINS service is not working on the router. Also you can try to access other PCs by computer_name. or computer_name.local if just computer does not work.

In case you can't ping the computers I would start with setting the same network and mask for them.