1. Click Start
2. Click Run
3. Enter winipcfg and hit either OK or the Enter key on your keyboard
4. In the window that appears, there should be a drop down box. If it says PPP Adaptor, change it to your ethernet adaptor.
5. Look for Physical Address. This is your MAC address.

1. Click Start
2. Click Run
3. Type cmd and press Ok (or Enter, if you have it)
4. In the screen that comes up (a black screen with white letters), type ipconfig/all and press the Enter key on your keyboard
5. In the information that comes up, you will want to look for Physical Address. This is the MAC address of your computer

  MacIntosh OS 8 or 9:

1. Click the Apple icon in the upper left corner of the screen.
2. Click on Control Panels
3. Click on TCP/IP
4. Click the Info button.
5. The Ethernet Address is the MAC address for your computer.

  MacIntosh OSX:

1. Click the Apple icon in the upper left corner of the screen
2. Open System Preferences
3. Click Network
4. Select the TCP/IP tab
5. The Ethernet Address is the computer's MAC address. If it is not displayed here, look for an Ethernet tab. Click that and find the Ethernet Address.