What is a good unique PC identifier?

Question

I've been looking at the code in this tutorial, and I found that it uses My.Computer.Name to save settings that shouldn't roam between computers. It's entirely possible, however, for a user to have two identically named PCs. If they wanted to have the same username on each PC, for example, they may very well end up with two PCs named Username-PC.

What are some good methods of identifying different PCs? Do PCs have GUIDs associated with them, or should I look into pulling the serial number off of some hardware? I don't care if the identification persists through reinstallation of Windows.

(The tutorial I linked is in VB.Net, but I'm implementing it in C#)

Answer 1

Some good identifiers:

• MAC Address: It's fairly easy to get at, and it's usually unique. However, it can be spoofed/changed rather easily, so it depends on how unique it needs to be.
• CPU Serial Number: It's not available on lots of older systems, but it's there. Check out this MSDN page. It won't change, but it's bound to a computer.
• HDD Serial Number: It's likely to not change, but can be a nuisance if the HD fails. Check out this MSDN page.

Answer 2

If you are on windows HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\ CurrentVersion\ProductId is unique per machine/per windows install. where as in some of the other answers like the MAC address, Proc SN, and HD SN will stay the same between windows reinstalls/dual boot situations.