I have 3 laptops that were running Win 7 and all seeing each other. I upgraded one laptop to Win 10. I can access one of the other laptops but cannot access the other laptop. When I try to access the Win 7 laptop from the Win 10 laptop, it asks for user name and password but does not accept the admin user name and password of the Win 7 laptop. All 3 laptops have the same admin user name/password. I followed John Hurst's Folder sharing on modern machines: http://www.experts-exchange.com/articles/16639/Folder-sharing-on-modern-machines.html
but that did not help. Any ideas?