The MAC address is your computer’s unique hardware number. It is also referred to as your computer’s physical address. When a host computer is connected to the internet, a correspondence table uses your IP to relate to your computer’s physical address on a local area network. This is how your router knows which computer to send an IP packet.
In essence, you can compare a MAC address of a computer to the finger print of a person. They are all unique and if the MAC address doesn’t match the MAC address that is being sent to the specific computer the packet will be ignored and then discarded.
This can be a way for viruses to be delivered specifically to a certain computer and not affect any other computers. A person can look up a computer’s MAC address and then theoretically assign a packet that contains a virus to that specific computer. Even if that person then passes a message to another computer, the virus won’t be opened. It will simply be ignored by the host and harmlessly discarded.
How can this address be discovered by someone? It is just as easy as submitting an IP query. By using a piece of software to reverse look up your MAC address. This can explain why your computer was affected by a virus that destroyed the mother board functionality, but a different computer that was connected to the same network was unaffected.
Even though this MAC address is just as simple to find as your IP address, as long as you have a decent virus and browser antivirus software on your computer to detect these things, you should have no problems with avoiding the aftermath of a virus entering and destroying your computer.