My laptop is not able to connect to WiFi Network after reinstal OS

Hello everyone.
I very much hope that anybody already met such headache problem as I did.
I have two laptops and a wireless network at home. The router is Atheros WAG 200G. Everything was Ok until I had to reinstall windows XP on my Toshiba P35-s609 with Wi-Fi card Linksys AR 500G inside.
After that my laptop cannot connect to my network. It can see a network but after trying to connect a message appears, saying the network is no more in range, pls refresh the list and try again. The other laptop Dell XPS m1330 connects fine, same as My Nokia N95-2 and xBox360.
The worse thing is my Toshiba is able to connect to some public network, but not a home one. I did not change any setting on the router prior to reinstallation. There was no such problem before that.
And I have tryied to install a Win XP system and to recover from a DVD which was provided by a manufacturer. Nothing helps.
EvenI have updated firmware for the router and installed all updates from Microsoft.
I was trying to copy my network settings from one laptop (Win Vista) to another (Win XP) but system says that not all of settings a presented.
I am almost broke my head on that issue. Is there anyone who can help me atleast with direction to go on that?
P.S. Funny thing. I have tried to connect using Ubuntu 08.04 Live CD. It works fine.  But Ubuntu is not for me as my work is in Windows unfortunately.

Many thanks in advance.

See if you can get newer driver/firmware for the wireless adapter from Linksys.

Have you run the Windows Networking Setup Wizard ?