None of your trusted wireless networks can be found

Question

Hello there,
We just bought a brand new 20" iMac 2.0 GHz Intel Core Duo last night, and we are having temporary Airport problems with it. We have updated the machine to 10.4.7, have run every single update in Software Update including the newest security updates, and have run the iMac SMC firmware update. So we are totally up to date on everything.
But we think we have discovered a bug in how quickly Apple's Airport software locates PROTECTED wireless networks.
We have a wireless router from Comcast, and we are wirelessly surfing the Internet just fine! Our wireless router works, and we're having no problems surfing the Internet. We have a 128-bit WEP security key enabled on our wireless network.
HOWEVER, 100% of the time without fail, we are having TEMPORARY Airport connection problems whenever we:
1. Wake up the machine from sleep.
or
2. Restart the machine.
or
3. Turn on the machine after it has been shut down.
Whenever we do one of these 3 things, we get an error message that says, "None of your trusted wireless networks can be found. Would you like to join the open wireless network 'linksys' instead?" ("Linksys" is our neighbor's unprotected wireless network.)
If we quickly click on the Airport menu at the top of the screen right when this message comes up, we can see that OUR OWN wireless network is NOT listed underneath the Airport menu at the top of the screen.
BUT -- by the time we answer NO to the above question, when we go back to click on the Airport menu at the top of the screen, sure enough our own network is now listed there! It is there, after about a 5-second delay. So we choose the name of our own wireless network from the Airport menu, and then we're connected just fine! It doesn't prompt us for our password or anything, b/c our password is already stored in our keychain.
So there seems to be something like a 5-10 second delay before the Airport software can see protected wireless networks, like our own.
But it's driving us crazy b/c we have to go through this little song & dance routine every single time. Is there any sort of a fix or a workaround for this that anybody knows of?
We've already been inside our Network system preferences and have chosen "Preferred Networks" instead of "Automatic", and have made sure that our network is at the top of the list (in fact, it's the only one listed there right now). Yet still, the problem remains.
Any ideas?
Thanks!
Scott
20" iMac 2.0 GHz Intel Core Duo   Mac OS X (10.4.7)  

Answer 1

A couple more thoughts. Have you checked with the maker of the router to see if there is a firmware update that the router might be needing? (usually can be found at maker's online support)
WPA2 is a much better encryption method than WEP - check and see if you can set up the router's encryption method as WPA2. Refer to this other thread
Cannot connect with WEP Encryption
I notice you mentioned this problem exists when you "Wake up the machine from sleep." I'm not sure it will help, but I have my iMacs set - at System Preferences>Energy Saver>Sleep uncheck the box "Put the hard disk(s) to sleep when possible" as that does you no real good to have it checked, and noticeable delays can occur due to that setting.
This final suggestion will not make a difference to your connection issue, but check System Profiler on its "Hardware Overview" to see if it shows:
Boot ROM Version: IM41.0055.B03
If not, there is a system firmware update, Firmware Update 1.0.1, available here [the SMC Firmware Update was included in Software Updates, so you undoubtedly already have it installed]:
http://docs.info.apple.com/article.html?artnum=303903
For further important info about this system firmware update, check out my Aug 24 2:21AM post in this other thread:
http://discussions.apple.com/thread.jspa?messageID=2976656&#2976656