Laptop Won't Connect To Any Encrypted WPA2 Wireless?

This is a 5-year-oldish Gateway MX-6124 laptop running under Win XP 2002, SP3. I'm using SureWest DSL, with an ISP-supplied ComTrend NexusLink 5631 Modem/Router. The router is set up as a Secure Network, using WPA encryption. The laptop wireless operation light toggles off/on correctly using Fn-F2 control keys.I can connect to an open or non-secured wireless router, & have verified that at my church, at the Public Library, and at Starbucks. However, I cannot successfully connect to a passworded secured wireless source. I tried to use a secured network connection at my church yesterday, and could not connect. It "tries & tries" and eventually gives up and displays a cannot-connect type of message.

The laptop has worked correctly for several years on my home wireless network. It only stopped working about 3 or 4 weeks ago. I cannot recall changing anything in setup; I probably did it accidentally.I've spent about 2 hours in a couple of sessions with SureWest tech support. They diagnosed router setup using direct connect to the router, plus they talked me through several attempts at configuring the wireless config setup on the laptop. Everything I reported to them on the config settings appeared to be just fine. They also deduced that the wireless config on the desktop & router was correct.SureWest techs finally concluded that something was wrong with my laptop software config or the hardware, disabling it from making a encrypted connection. That sounds right to me, now having witnessed the secured connection failure described above, at my church wireless site.

I've looked at all the refs & things I can think of, plus followed step-by-step directions a couple of times with the SureWest techs. They rightfully pointed out that they could not make a tech support repair call on what did not appear to be a SureWest-related problem.I can easily make screenshots of any config screens needed on the laptop & upload to this forum.