Question : How do I find out another pc's MAC address

I want to reserve an IP address already in use and establish a larger DHCP pool around it.  The IP address in question is on Oce print server with all of the printing control screens.  I can't shut it down or screw with it in any way.  While trying to reserve that IP the DHCP server asks for the MAC address to setup the reservation.

Answer : How do I find out another pc's MAC address

If you know the IP address of that server ping it and check your ARP table. You will see the MAC address corrosponding to the IP address.