Airport Connection

Hi I am new to the forum I and hope I am posting my question in the right place. From a week ago my computer stop finding any wireless connection. I turn the airport on and it saids scanning, but does not appear any network in the list to connect. Recently I was erasing a lot of stuff on the computer and I do not know if I erase like a driver of the card because last week it was working perfectly with any wifi near by. Trying to repair it, I erase everything in the computer and reinstall Snow Leopard, but it continue making the same thing. The airport saids scanning but does not appear any network. Can someone please help me????