Unable to join, leave or create a homegroup

I have a couple of Win7 PCs in my home network. I bought a tablet/notebook (Asus T100) with Win8.1 pre-installed.

I was able to join the existing homegroup with the tablet PC without any problem. After a short while the tablet exhibited a problem that I couldn't resolve so decided to reset the machine to factory default. I was then able to re-install the couple of applications I needed and all was well until I looked at the homegroup settings. It looked as though the reset had retained some of the settings for the homegroup but neither of the Win7 PCs could be seen.

I then tried to leave the homegroup but the "Couldn't remove your computer" message appeared. I tried accessing the "change password" and "display password" options but nothing happens. I've tried the troubleshooter on all 3 PCs without success.

I tried leaving the homegroup on the two Win7 PCs and this has worked OK but I still can't leave the homegroup on the Win8 PC in order to join a new one that I will create.

I've tried some of the fixes from here (stopping the and disabling the homegroup services and deleting the files in the C:\Windows\ServiceProfiles\LocalService\AppData\Roaming\PeerNetworking folder without success.

Any ideas anyone?