or recorded such as the MAC address of an on board NIC and compared the old to the new.
I don't think it was. Here's the deal. I bought a new computer. 2 weeks later the picture on the screen would "freeze" on me after my computer sat idle for several minutes. My keyboard input in the back also wasn't working. I had to use a keyboard with a USB plug instead. I took it back. Was told it was still covered under manufacturer's warranty. The electronic's store sent it to them. 6 weeks later I get it back and was told they had to replace the motherboard. Well guess what?? It's still freezing!! Plus the keyboard plug is not working. I was also expecting to re-install my programs (I-Tunes, Norton, etc) but they were still there. I figured if they replaced the motherboard they would have had to restor the OS system as well. But that clearly didn't happen. Is there a way to know if the original motherboard is still in there?