To ensure reliable networking between your computers, make sure that the Network type is set to "Private" or "Home".

The following article explains how to do this in Windows 7, Windows 8.1 and Windows 10:

http://www.online-tech-tips.com/windows-10/change-from-public-to-private-network-in-windows-7-8-10/

Alternately, http://www.gymassistant.com/kb/www.dummies.com has excellent explanations of what it means to have a Public/Private network connection and how to switch your network connection to Private.

Windows 7

https://www.dummies.com/computers/operating-systems/windows-7/how-to-change-a-network-type-in-windows-7/

Windows 10

https://tinkertry.com/how-to-change-windows-10-network-type-from-public-to-private

Alternately, http://www.dummies.com/computers/operating-systems/windows-10/how-to-set-a-network-profile-in-windows-10/