MacBook Air not showing up under network HELP

The only changes to the computer was the latest Mac OS update. Now under network in explorer it would show my PC then my MacBook Air then PSF. I made a few changes and it does not show up at all, when it did it was asking for the network password login ? I tried plenty of variables and no way to log on. I can open up my pc and PSF just not the MacBook Air when it was under network

 

Bump? Anybody? When I select my MacBook air I keep getting the network security pop asking for a password and username?.