Home Network and ipv6

[#1]

I am having trouble setting up the home network between two W7 (home and Professional) computers. I have done it successfully previously but since re-installing on both machine last year I didn't need to have one... till now.
Using Passwords from either machine for other doesn't appear to work and the troubleshooter hasn't been particularly helpful, either.
The latest issue when attempting to add the laptop using the PC's HomeGroup password is:

Quote

You local network must have ipv6 enabled to create or join a HomeGroup. To enable ipv6 start the HomeGroup troubleshooter.

which didn't solve anything. I don't remember having to enable ipv6 before -unless it already was.
Perhaps O should start from scratch but not sure the best way forward. I simply want to be able to transfer some files between the two machines. For smaller files I use SkyDrive but some of the files I wish to transfer are over 8GB.
I don't want to use a Flash drive as I don't always want to move around the house when I should be able to have the convenience of a HomeGroup.
Any advice would be greatly appreciated.

[#2]

I seemed to have resolved it - I hope.
Haven't yet tried to move/copy files but ipv6 was already enabled on the PC but not on laptop which it previously must have been.
ipv6 was a bit of a red herring to me as I assumed it would not be relevant as I was not on the ipv6 trial
Edit: File copying is working

[#3]

Quote from: Mav

I don't remember having to enable ipv6 before -unless it already was.

My my W7 HP I have IP6 installed and enabled but it isn't used as my router is IP4. I was under the impression that all W7 systems had IP6 by default.

[#4]

Sorry for the misunderstanding.
On the Laptop ip6v was installed but not enabled whereas it was already enabled on my PC - bot sure why the difference in setup as I never actioned it (maybe difference between how W7 Home and Pro is setup?).
I was just a little shocked that W7 reported that a HomeGroup can only be setup and used if ipv6 is installed and enabled.

[#5]

It's due to a shift in how Windows sets up peer-to-peer networks/groups. Whilst previously computers were identified using Netbios names it is now done using the Peer Name Resolution Protocol (PNRP) and it is this aspect that requires IPv6.