In computer networking, a Mac Address is a Media Access Control address (MAC address) is a unique identifier assigned to most network adapters or network interface cards (NICs) by the manufacturer for identification, and used in the Media Access Control protocol sub-layer. If assigned by the manufacturer, a MAC address usually encodes the manufacturer's registered identification number. It may also be known as an Ethernet Hardware Address (EHA), hardware address, adapter address, or physical address.
Whenever you are trying to do something wrong thing like hacking then you must first change mac address your computer or pc.There is a software available which can be used for changing mac address.
SMAC MAC Address Changer 2.0.5
SMAC is a powerful, yet easy to use MAC address changer for Windows systems, regardless of whether the manufacturers allow this option or not. The new MAC addresses you change will sustain from reboots. Features: change MAC address in 3 clicks, validate MAC address, generate random MAC address, view MAC address, IPConfig button, view complete network adapter information, load MAC address list, show MAC change history, show manufacturer of MAC address. Version 2.0.5 includes unspecified updates.
Download From here