Things You'll Need
Instructions
Plug in the Ethernet cable into the back of your Xbox 360 through its Ethernet port. Plug the other end of the cable into the Ethernet port in the back of your laptop.
Turn your laptop on, click "Start", and go to "Control Panel". From here, find the "Network and Sharing Center", and left-click on this icon.
Select both the wired and wireless connections on your laptop, and right-click. You will be given the option to "Bridge" the connections. Click this option.
Start up your Xbox 360, and check the connection to Xbox Live. Your console should now be connected wirelessly to Xbox Live using the laptop's PC wireless card as an adapter for the Xbox 360.