Can't add one computer to the homegroup

[GraphicFunn]

I have two Win7 Pro 64bit desktops and one Win7 32bit laptop that I am trying to set up a homegroup for. The laptop and newer desktop systems are using Wifi and the older desktop is hard wired. All on the same network box. All are set to Home network. All three have unique computer names. I am able to create a homegroup on the older desktop and then the laptop shows the join homegroup option which I can join. I can see all the library files from both of these systems. But when I go to the newer desktop it only gives me the option of creating a homegroup not joining. I can create a homegroup on it but it still does not see the other two computers. Any ideas? thx

 

[samuria]

Is it running ipv 6 as it's needed for homegroup

 

[GraphicFunn]

Thanks for the thought but IPv4 is what is here. If IPv6 was required I would not be able to have a homegroup on any of the computers and I can on all of them. Its just that the second desktop can not join the homegroup the other two belong to. It does create its own.

 

[samuria]

It is [SOLVED] Reasons For Keeping IPV6 Enabled in Windows? - Windows Forum - Spiceworks

 

[GraphicFunn]

I ran Test your IPv6. earlier and it told me "No IPv6 address detected" and "You appear to be able to browse the IPv4 Internet only. You will not be able to reach IPv6-only sites." So I assumed no IPv6 but later I checked Local Area Connection Properties and it does show IPv6 checked as well as all the other choices. So I guess this means I have it and that is not the reason I can not join the homegroup?