Thanks for the fast reply.
I uninstalled and reinstalled the OneNotePowershell.msi, ran the Enable-OneNote.ps1 and came up with the same error (Add-PSSnapin Microsoft.Office.OneNote not found).
I think I need to take a step back and ask a more Powershell centric question.
When I issue get-pssnapin on my laptop it shows that I have :
Name : Microsoft.PowerShell.Core
If I search my laptop for Microsoft.PowerShell.Core, nothing is found. But Microsoft.PowerShell.Core apparently is an installed snapin (module). So when I initially installed PSv3.0 the install process must have performed an add-pssnapin xxxxx to get the Microsoft.PowerShell.Core installed??
So does add-pssnapin xxxxx use xxxxx or is xxxxx an alias for another file??