If you're using Windows Vista, 7 or 8, you can access your MAC address by going to the Network and Sharing Center resources (in Control Panel). Once there, click on the name of your network connection.
A window opens. Locate the "Details" button and click on it. A list of all the connection settings opens. The MAC address is listed as "Physical Address".
If you want to access your MAC Address from an Apple computer, go first to the apple (top left), and there, About this Mac.
In the window that opens, click 'System Report ... ".
In the new window, select Network in the left column and the type of connection you want the MAC address (wi-fi, if you are connected to wifi, Ethernet if you want the Ethernet cable). Looking to the right MAC address.