How to get a unique identifier of the computer? [duplicate]

Question

I'm writing a game server in Java and I need a way to get a unique identifier for a computer (Multiaccount protection), target platform is Windows >= XP. I tested many ways to do it with pure Java and JNI:

• MAC Address - Very easy to change, high collision chance
• (JNI) Motherboard SN - It is not always, high collision chance
• (JNI) Diskdrive SN - Can't detect disk drive by disk letter with WMI, little collision chance, doesn't work on Windows XP (Hasn't SerialNumber field)
• File in hidden folder - Doesn't saves after Windows reinstall, can modify or delete if i know where it.
• (JNI) Windows GUID - high collision chance, doesn't saves after Windows Reinstall.

Any another way?

Answer 1

I can suggest you to use CPUID I ve used it to my software licensing

Cheers :)