Rename-Windows-Without-Reboot.ps1

function RenameComputer($ComputerName)
{
   $computer = Get-WmiObject -Class Win32_ComputerSystem
   $computer.rename("$ComputerName")
      
   Remove-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -name "Hostname" 
   Remove-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -name "NV Hostname" 
   
   New-PSDrive -name HKU -PSProvider "Registry" -Root "HKEY_USERS"
   
   Set-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\Computername\Computername" -name "Computername" -value $ComputerName
   Set-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\Computername\ActiveComputername" -name "Computername" -value $ComputerName
   Set-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -name "Hostname" -value $ComputerName
   Set-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -name "NV Hostname" -value  $ComputerName
   Set-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" -name "AltDefaultDomainName" -value $ComputerName
   Set-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" -name "DefaultDomainName" -value $ComputerName
   Set-ItemProperty -path "HKCU:\Volatile Environment" -name "LOGONSERVER" -value $ComputerName
   [Environment]::SetEnvironmentVariable("COMPUTERNAME", "$ComputerName", "User")
}

Weirdly this isn't working on all systems. Digging into it now.

This doesn't seem to be doing anything:
$computer = Get-WmiObject -Class Win32_ComputerSystem
$computer.rename("$ComputerName")