I just loaded my desktop machine with Win7. While it was an XP machine I was able to share with all computers including Macs in my house by setting everyone to the same WORKGROUP. I connect the desktop to a WiFi router via Ethernet cable and all others connect via WiFi. I have turned on file sharing on my Library folders (documents etc) not by using Homegroup but rather the old Workgroup approach. For each folder I want to share, I right click and go to sharing which gives my Homegroup options or the option to connect to a specific user, I set that to 'Everyone' and click Add. I can intermittently see my other Windows machine (XP) and look at all of the shared folders. But my Network shows only my own computer now. The XP machine also cannot see me, when I go to "view workgroup computers" from the XP machine it says, workgroup not accessible, you might not have permissions..... It was able to view the 'public' folder but nothing was inside, it cannot do that now either. As far as the Mac computer goes, I have seen it and been able to view folders and documents from the Win7 machine, but now I cannot see it and I've changed nothing.