Airport card won't auto select my AirPort network at boot up

Question

I have two AirPort express routers in the house, configured together (to increase range) on one network, "Aspen". Its the only network I have. When I first set up my Mac several years ago I used the AirPort wizard. After initial config, my Mac would always automatically select the wireless network "Aspen" at every boot up. Over time, I started to see my neighbor's various networks listed too, but, the AirPort card always auto selected and connected to my network.
Somewhere along the way (with various network reconfigs happening to add the second router, reset a password so someone's WIndows machine could use the network, etc..) somehow my config got munged and for the last year or so my AirPort card would not auto connect. I'd have to manually select "Aspen". In the last few months, auto select has begun working again, but, it always, always selects my neighbors network, and I have to manually switch it over to mine.
I've used the Help docs below. I've got it set up exactly as they're saying. "Aspen" is the ONLY network on my AirPort list. When I boot, it says, "I can't find your network. Would you like to connect to "neighbors network"? What can I do to reconfigure this to work correctly?
Thanks so much!
Choosing preferred AirPort networks
By default, AirPort attempts to join the wireless network your computer was most recently connected to.
If you are in an environment with multiple wireless networks, you can set up your computer to join a preferred network when you start your computer, wake it from sleep, or turn AirPort on.
AirPort keeps track of the wireless networks your computer has connected to, and lists them in the Network pane of System Preferences.
To choose a preferred AirPort network using Mac OS X 10.4:
Open Network preferences, choose AirPort from the Show pop-up menu, and click AirPort.
Choose "Preferred networks" from the "By default, join" pop-up menu, and select a network from the list.
You can add wireless networks to the list by clicking the Add button, and clicking on the Network Name pop-up menu. Choose a network and enter a password for the network if necessary. Use the Delete button to remove a network from the list.
To give a network the highest priority, drag the name of the network to the top of the list. This is the network AirPort will attempt to join first.
If you are using Mac OS X 10.3, choose "A specific network" from the "By default, join" pop-up menu, and either type the name of the network in the Network field, or click the Network pop-up menu to display the available networks, choose one and then enter your password for the network.
You can set additional options to control the way your computer joins available networks. Click Options and choose an option from the "If no preferred networks are found" pop-up menu.
If you choose "Ask before joining an open network," you will be prompted when an open network becomes available. If you choose "Automatically join an open network," you will not be promoted, and will automatically join an open network when it becomes available. If you choose "Keep looking for recent networks," AirPort will continue looking for networks you have already joined, and automatically join the network when one is found.

Answer 1

You might try the steps in this Knowledge Base article;
http://docs.info.apple.com/article.html?artnum=304482
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