Airport Extreme can see networks, can't connect to any

Question

I recently bought an iMac G4 (1Ghz, 17") on eBay and am having problems getting the Airport Extreme card to connect to any network. It came with 10.5.1 installed and I've updated it to Leopard 10.5.8
I'm a bit of newbie with this Mac, but am learning quickly and I've tried to do my due diligence research prior to posting. I think I've tried every solution I've found recommended on forums for others with my problem.
Here's the basic info on what I've tried (by themselves and various combinations):
-changing the channel the network operates on.
-changing from WEP to WPA
-changing to no security at all
-changing to manual DHCP setup
-disabling Wireless-g only to allow b & g, and I've tried allowing only g
-I tried moving AppleAirport.kext to the desktop to let the system rebuild it with a restart - it was not rebuilt so I moved it back in and restarted again
-reset your router
-made sure router firmware was up to date
-creating a new network location
-went to Library > Preferences to delete com.apple.internetconfigpriv.plist and com.apple.internetconfig.plist but there were no files with those names in that folder
None of these options changed any response to the ways I've tried to connect to the internet.
It connects fine through the router with an ethernet cable. With this option it takes the network address 192.168.1.5
I also tried to connect to my neighbor's open network, with that network it will either timeout or ask me for a WEP password, which isn't needed.
These are the errors I get when trying to connect to my own network wirelessly:
-When I go through Network Setup Assistant, I get the error: "The password you entered is invalid." Even though I know it is correct (checked and rechecked to make sure all keys were working in a text file).
-When I go through System Preferences > Network I get a Connection Timeout every time it tries to connect.
-When I go through Network Diagnostics through Safari, it can't find any Apple Wireless Devices to work with or it gives me a connection timeout.
My iPod Touch 2nd Generation has never had a problem connecting to this router or the neighbor's open network.
Neither have any of my three Dell laptops.
AirPort Card Information:
Wireless Card Type: AirPort Extreme (0x14E4, 0x4E)
Wireless Card Locale: USA
Wireless Card Firmware Version: Broadcom BCM43xx 1.0 (4.170.25.8)
Current Wireless Network: wireless network not available
If it matters, I've got an Actiontec router and I'm connecting to Verizon FiOS.
Thanks in advance for any recommendations. I guess if the Airport Extreme card [or software] won't work I'll just have to try a USB network adapter (want to avoid this as this iMac only has USB 1.1).
Ed

Answer 1

Hi there!
Were any software install and restore discs included with the computer to support
the license and ownership, maintenance and help upkeep the computer's OS X?
Not sure where to begin in resolve the connection issues you have presented,
since I am almost under siege in my offline life with problems others foist on me.
Your issue may be in part due to a scenario where enabling WEP can causing
an issue of a self assigned IP address; the address sometimes may be just a
default and not that of the router's giving one to the computer. You can some-
times reset and hope the router can give you a new different IP address or DNS.
There usually is something else to this, if that is the case.
However, to make sure the computer itself is in a good state of health, and you
have some of the basic means at your disposal, (or to know what you have) is
why I am replying. And once that is mostly a certainty, to see if the settings to
choose the AirPort as a viable Network choice in the System Preferences, with
wireless on top of the available options open to the computer. You can drag in
order of desired connection type, the Ethernet, dialup, Airport, etc - means of
making or sustaining a connection in the Network panel. If these items are not
correctly chosen, the available wireless Airport won't work. And the status of
the Airport connection won't be visible in the main menubar header either.
Have you been through some of the several Apple Support documents on topic?
• Mac OS X: Connect to the Internet, troubleshoot connection & set up small network:
http://support.apple.com/kb/HT1714?viewlocale=en_US
• Mac OS X: Troubleshooting a cable modem, DSL, or LAN internet connection:
http://support.apple.com/kb/TS1317
• AirPort troubleshooting guide (primarily settings & base station)
http://support.apple.com/kb/HT1401?viewlocale=en_US
For computer basics, to check and do simple software maintenance of the Mac
OS X, you can boot the computer in SafeBoot (shift key held on startup until a
login window appears) and from GO in main Finder window, see Utilities folder
in the drop-down menu, and look for then launch Disk Utility from the Utilities.
In Disk Utility, choose the Macintosh HD, then 'repair disk permissions'. You
may be able to later click on the hard drive icon of the Brand of the HDD as
seen in the same sidebar where the Macintosh HD was located, and choose to
'verify' the hard disk drive from the choice in the Disk Utility panel then available.
When done with these items in Disk Utility, quit it; then restart the Mac normally.
{For other levels of Disk Utility repair on the hard disk drive, you need to boot the
computer from the OS X Installer's disc#1 and choose Disk Utility from its menu
bar prior to actually running that Installer. The drop down menu bar has options
and select them carefully; since you can do quite a bit to the computer's drive if
the wrong item is chosen out of turn or when not needed. A booted disk utility is
in a position to act more thoroughly on a hard disk drive that is then unmounted.}
If the computer is in a good state of preventative maintenance and permissions
repairs, etc the main issue would be in the choice of settings to access the internet
via the means at the computer's disposal; and choosing the hardware path in the
Network panel of System Preferences is one of the main portals. There are several
items in here, including being able to check-mark and move the order of importance
the main items in a Network preference window, so the computer chooses them first.
If the antenna cable and other connect to/from the AirPort card in the base of the iMac
is properly pressed firmly into position and the card is OK, the physical and electronic
paths should be assured; as far as that goes...
Some of the changes to settings may not have been necessary or help in connecting;
so I am not so sure what ones would need to be changed back to their defaults.
Good luck & happy computing!