If you are connecting directly to your desktop computer, then make sure both of the cards are in Ad-Hoc mode. If you have more computers on your network, get an access point. To take full advantage of your G card in your laptop, get a wireless G access point, but wireless B should work also. Once you get your access point, make sure that the cards are in infastructure mode.
Also, you might want to check the workgroup that your comptuers are set up on. It's usually "MSHOME", but every once in awhile it's set to "WORKGROUP". In order for your computers to see each other, they must be on the same domain.
Go to "My Computer", then "System", then click on the "Computer Name" tab. (Win XP) It also might be known as Network ID or Network Name. Make sure the "workgroup" names are the same on both computers.
