Presumably you have already downloaded and installed AirPort utility?
It is best done over Ethernet cable. Connect your laptop to LAN port at the back of AirPort Extreme.
If your Airport Utility finds the AirPort Extreme but you cannot connect go to File > Configure Other and type in the IP of the AirPort Extreme (default 10.0.1.1 and default password "admin").
Please post back.
Yes. I downloaded airPort Utility 5.6.1 for Windows. I'll also try the setup using a Macbook to see if this makes a difference.
I tried the Manual setup and get the error -4 message. Do you know what the -4 error message means?
Tried the soft reset, hard reset and factory reset options and none fixes the problem. Since this is a new unit, it should already have the default configuration, but I figured I'd try the reset anyway just in case.
Will try your suggestion to connect the laptop using the ethernet cable when I get home this evening and post the results.
Using the "Configure Other" did the trick. This allowed me to configure the base station for a secured wireless network. Strange that the airPort Utility cannot find the airPort when it scans for base stations. So I have to use "Configure Other" whenever I want to make any changes.
Thanks tzbikowski and Bob Timmons for helping me to resolve my setup problem!!!