>Now, what does mac mean in this case?
It's the unique internal address assigned to your network card. If you don't have a network card, the OS generates a pseudo MAC address for its purposes. That's why when you don't have a network card, it's theoretically possible to get duplicate GUIDs (although extremely unlikely) from different machines.
Larry Miller
MCSD
LWMiller3@verizon.netAccumulate learning by study, understand what you learn by questioning. -- Mingjiao