another way is (and i'm using that) to read the motherboard loading program (that is a program ROM-BootStrap i guess) that executes what you saw when you restart your computer...

this program starts at 0x000fe000 in physical memory, and should contain in it and the motherboard serial number (because it is showed on computer startup)

so you can build a CRC on this and...there you have it...

also, you can combine this with another method, but currently i'm using this and i'm pretty satisfied...

DANI