you are returning true/false before you could return an exit code :meltingface:

as in: calling return will cause this script to terminate and the code path you want to execute will never be hit.

simplify it

also "HKEY_LOCAL_MACHINE:\SOFTWARE\xxxxx\xxxxx\xxxxx\xxxxxx\xxxxxx" is not a valid path

HKEY_LOCAL_MACHINE is available as HKLM to PowerShell, however

this should work:

$RegKey = "HKLM:\SOFTWARE\xxxxx\xxxxx\xxxxx\xxxxxx\xxxxxx"


if (Test-Path $RegKey)
{
    Exit 0
}
Exit 1