Thank you for your response. Actually, the problem was a bit unusual- when I reinstalled Win 7 after the crash, the registry for the ethernet card did not populate correctly. So if you did an ipconfig/all you would not realize the problem. However, when using the PTC batch file cpu_id, you could get the physical address but also a warning about the registry having an issue. My ethernet card is a Broadcom so I just loaded and installed the latest driver and this solved the problem. When trying to install, the PTC interface could not properly identify the physical address of the computer.