Incorrect Mac Address Prevent Internet Connection

Last Tuesday when I was working on my things, my colleague came up to me and asked me to take look at one computer which could not go online. He had already tried many ways to fix it. But none of them worked. The computer was an Acer computer and the Windows was just installed there. The NIC card driver was first installed using driver tools and reinstalled with the driver from the manufacturer. The NIC worked in DOS after the DOS driver was correctly loaded. I went to the computer and ran “ipconfig /all” in the command line and found the Mac Address (Physical Address) for the NIC card was 00-00-00-00-00-00!. Then I opened Device Manager to found the NIC and went to the Advanced Tab of its properties page. Set a value in the Network Address and saved the setting. After doing that, the computer came back online again. That was the first time to see the invalid Mac problem. I think it should be caused by the incorrect Windows driver. I do not want to write everything here in detail to show how to do it step by step, so I googled something for you: How to Change or Spoof MAC Address in Windows XP, Vista, Server 2003/2008, Mac OS X, Unix and Linux and a small utility called Macshift. I did not test the Macshift. Do it by yourself if you need.