IMac G4 suddenly can't connect with Airport -- password not recognized

Question

I have an iMac G4 running OS X 10.4.11 with an airport card installed that until recently connected with an Airport Extreme base station in the next room. Recently, the connection fell out, and when I try to reconnect with the network, it says it won't recognize my password. (We use WPA2 personal security.) This failure occurs even though my iPad can hook up, as can my wife's G5 and her iPad. There was a problem with an Extreme router, but my wife reset that, and when she did she used the same password that we've always used. So, in essence, my G4 is the only piece of equipment that can't talk on the network.
An Apple helpline person said he suspects my computer is just getting old; it's around 7 years old now. I'd hate to think that's the case. Could this be a hardware and not a software problem? Any suggestions of what to do?

Answer 1

I suspect that that "Apple helpline person" is just getting lazy...
It might help to reset the connection settings on your Mac using these steps one at a time until the problem is resolved, recognizing that, depending on your problem, not all of these steps will make sense.  They're also tailored to OS X 10.5 and 10.6, but they should work with OS X 10.4.
1) Use the AirPort menu bar item to turn AirPort off, then on again.
2) Try to select your Wi-Fi network from the AirPort menu.
3) In the Network panel of System Preferences delete the AirPort item from the left column, then add it back.
4) In the same panel as (3), define a new location and see if you can make that work.
5) In the same panel, select the AirPort connection item, click the "Advanced" button, select the "TCP/IP" tab, then click "Renew DHCP Lease".
6) In the folder /Library/Preferences ( _not_ <yourhomefolder>/Library/Preferences), move the folder SystemConfiguration onto the Desktop, then restart your computer. See if you can now make your AirPort connection work.
These steps may not help, but they'll only take a couple of minutes to try.  Before you try these, if you have any special network settings on your Mac for things like DSL credentials, note all your network settings, because the latter steps will destroy them.  If you got all the way to the last step, if things don't work any worse than before, you can trash the saved SystemConfiguration folder.