Is to change the mac address without changing the computer name. After testing for a few days, it seems that win7 can be modified with tools, and mine is modified with tools. At this time, it is ok to restart the computer and restore the mac. Win 10 needs to modify the value of mac address in Device Management-Network Device-Advanced. Restarted the computer several times, so far there is no problem. It's no use reinstalling the system. The Mac address is dead and can only be changed. If you encounter this problem, modify the address directly.