[AccessD] Computer Identifier

Good Afternoon Everyone

I am trying to confirm that a computer is eligible to open a distributed
.mde file by the startup screen first checking to see if it's identifier
exists in a separate password protected file.  To do this I need to be able
to extract an unique identifier for each computer (say the Windows Registry
key or something).

Can anyone offer a suggestion of a PC identifier to use and how I would
retrieve it using code?

TIA
Cheers
Selina