This command can be used to add a local user account to a group (such as administrators) using PowerShell.

• Replace ComputerName with the hostname of the computer
• Replace username with the username of the account to add to the group

([adsi]"WinNT://ComputerName/administrators,group").Add("WinNT://ComputerName/username,user")

If on a domain, use the DomainName instead of the ComputerName.

([adsi]"WinNT://ComputerName/administrators,group").Add("WinNT://DomainName/username,user")

This command can be used to view the members of the group.

gwmi -query "select PartComponent, __Server from Win32_GroupUser where GroupComponent=`"Win32_Group.Domain='$env:Computername',Name='$localgroup'`"" |
  % { [WMI] $_.PartComponent } |
  ft -a Domain, Name, FullName, Description