Get the MachineGuid from
    HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MachineGuid

def get_nt_system_uid():
    """Get the MachineGuid from
    HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MachineGuid
    """
    try:
        import _winreg as winreg
    except ImportError:
        import winreg
    lm = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
    try:
        key = winreg.OpenKey(lm, r"Software\Microsoft\Cryptography")
        try:
            return winreg.QueryValueEx(key, "MachineGuid")[0]
        finally:
            key.Close()
    finally:
        lm.Close()