that it is not the macbook. Sadly I have run into a few that insist the product is defective even after I correct or replace the router. The fault must be in the laptop. I read the thread over again and see nothing amiss with the macbook.
Have them check to see if they enabled filtering on the router.
Last time I posted this note (see below), it was suggested that I make sure I have the password for this network in my keychain. I'm back at the home where I have the problem and I do have their password in my keychain. They assured me that they haven't changed their password. I don't want to do any manipulating of their network for fear that I'll bring it down and not be able to fix it, so unless there are any other thoughts on this, I believe I'm doomed to use their neighbor's network which of course I don't feel good about.
I travel frequently to the same location and with my old iBook I never had trouble connecting to their wireless network. But my new MacBook won't connect. It will however connect to a neighbor's network albeit slowly. And then the other day, it stopped connecting to that network too. I've been in several other locations with this MacBook and it always connects to other wireless networks. What could be the problem? I've called Apple Care and have gone to the Genius Bar but everything looks fine on the MacBook.