Hi Daniel, I don't know much about CPU serial numbers, but from what I've read they don't exist in modern CPUs. See e.g.: http://en.wikipedia.org/wiki/Processor_Serial_Number#Controversy_about_privacy_issues
When I ask for the serial on my CPUs (on linux) I just get "none specified".
It might be possible to get the motherboard serial number, although I haven't managed to get it on Linux without sudo'ing (not a problem on Windows as far as I can tell).