Did you know you can get any Windows computer’s MAC address without leaving your chair?
Simply open a command prompt and type:
getmac /s viper
If you are not on a domain, you may have to use the /U switch and pass the name of an administrator account on the other computer.
getmac /s <machine> /u <username> /p <password>
If you have issues with that, you can always use the arp command. You can use the ping command to figure out the IP address of a computer name, and then use this syntax:
arp -a <ipaddress>
There are probably a lot of other ways to get the information, but this will work.