Como você está executando o Vista Starter Edition, seu sistema não pode fazer parte de um domínio. Isso tem implicações para o WinRM (e PowerShell Remoting) - o seguinte é da ajuda interna do Powershell:
ps> get-help about_remote_faq | more
No final, isso diz o seguinte:
CAN I TEST REMOTING ON A SINGLE COMPUTER (NOT IN A DOMAIN)?
Yes. Windows PowerShell remoting is available even when the local
computer is not in a domain. You can use the remoting features to
connect to sessions and to create sessions on the same computer. The
features work the same as they do when you connect to a remote computer.To run remote commands on a computer in a workgroup, change the
following Windows settings on the computer.-- Windows Vista:
Create the following registry entry, and then set its value to 1: LocalAccountTokenFilterPolicy in HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System You can use the following Windows PowerShell command to add this entry: new-itemproperty ' -path HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
' -name LocalAccountTokenFilterPolicy -propertyType DWord -value 1