• All network interfaces have a MAC address."Why is Folkert frowning?" is Copyrighted by Flickr user: Frenkieb (Francis Bijl) under the Creative Commons Attribution license.
  
  

How to Find the MAC Address

• The exact procedure for determining a MAC address is going to vary depending on the operating system you are using, but the procedure will be nearly identical for most modern flavors of Microsoft Windows. Simply click on "Start," then select "Programs/All Programs." Once there, open the "Accessories" folder and select "Command Prompt." In the window that opens, type in "ipconfig /all" to display your network information. The MAC address will be listed here as "Physical Address."
  
  

Missing Hardware

• The MAC address is the hardware address assigned to a network interface. Before you do anything else, you want to be sure that your computer does indeed have some sort of network interface. If you need to connect to your network via an Ethernet cable, be sure that you have a network interface card in the computer. If you intend to connect via wireless, be sure that your computer has a wireless card installed.
  
  

Corrupt or Missing Device Drivers

• The device driver is the piece of software that allows your operating system to communicate with a particular piece of hardware installed in your computer. Every piece of hardware installed in your computer will have a corresponding driver. If your computer is not registering a MAC address and the hardware is present, the device drivers for it may not be installed. If they are present, they may need to be removed and reinstalled.
  
  

Failed Hardware

• The sad truth about electronics is that they will fail sooner or later. In the case of computer hardware, this failure may result in your computer not being able to detect the device at all. It may also manifest in the form of your computer recognizing the device, but not being able to use it properly. If the device is present and the drivers are installed and functional, you may need to replace the networking device.
  
  

Corrupt Operating System

• In a complex operating system, there are many components, programs and snippets of software that all work in concert to operate the computer. Sometimes, it is not the fault of the device itself or the device driver at all, but the operating system that is running on the computer. It is a far less common cause of the loss of a MAC address, but it is one that must still be considered.