Change or spoof a MAC address in Windows

Step 1: Click on Start, then Control Panel, then Network Connections, and right-click on the network connection you want to change the MAC address for and select Properties. It will normally either be Local Area Connection or Wireless Network Connection.

If you are using Windows Vista, you have to go to Control Panel, then Network and Internet, then Network and Sharing Center, and then Manage Network Connections.
Step 2: On the General tab, click the Configure button

 Step 3: Now click on the Advanced tab and click on the “Locally Administered Address” property or the “Network Address” property.
 By default, the “Not Present” value is selected. Go ahead and click on the Value radio button and enter in a new MAC address. The MAC address is a combination of 6 pairs of numbers and characters, i.e. 40-A2-D9-82-9F-F2. You should enter the MAC address without the dashes.

You can check that the MAC address has been changed by going to the command prompt and typing in IPCONFIG /ALL. Go ahead and restart the computer in order for the changes to take effect.
This is the simplest way to change your MAC address in Windows. You can also do so via the registry, but it’s much more technical and probably not required by most people.