How can I see Windows PCs on a Mac and vice versa on a home network?
You need to specifically enable Windows File Sharing on the Mac.
By default just checking 'File Sharing' will enable [I think, it's been a long time since I set up a raw machine] SMB &amp; AFP, but not specifically Windows.

System Prefs > Sharing > Options…  



If you need to specify a Workgroup, that's done from Network > Advanced… > WINS



One thing to be aware of is that if one of your non-Mac machines isn't set to be Master Browser, then the Mac can often force an election &amp; win, even if it wasn't supposed to.
Depending on which machine is most likely to be on at all times, you may need to force that to be the Local Master.

This is a good article on how to set it on multiple platforms - http://petestechblog.com/archives/847 - there's a bit much to précis here.