two computers not coordinating

I have a pc and a laptop connected to a wireless home network. Home share isn't working between the two, even though it had been. This doesn't seem to be a network issue. Both are connected ... internet function is fine ... wireless printer function is fine.

I have turned off and logged back in to both computers. One of the computers appears to see the other, but does not list some recent additions to the music library.

The other computer does not show a homeshare library icon even when both are signed in.

Any idea what is wrong?