First of all, thank you all for the very helpful instructions, tips and tricks. I used Mandrake Linux 9.0-9.2 a few years before and then stopped using it after I changed a notebook. Now I am using a Dell Inspiron 600m with Windows XP and Mandriva 2006 dual boot. I am still a newbie and have been really confused about the wireless connection problem.
My network card is Intel PRO/Wireless 2100 3a pci adapter and is working perfectly fine in Windows so there is no hardware failure. I read through ndiswrapper installation notes and many other sites and had no problem getting the driver to work. The network card is strangely recognized as 2100 3b but the driver is properly installed and the card recognized by Linux. And I had no problem using iwlist and iwconfig for all the configurations. Everything seems to be fine. I also used all of beesea's instructions on how to get wireless working with ndiswrapper (https://mandrivausers.org/index.php?showtopic=14972) and wlan0 is recognized, brought up at boot, AP found, essid and open WEP key properly set up. But there is no connection. Whenever I try to connect, nothing happens. I tried to ping the router and I got "network is unreachable". That's the only error I can see now after two days of struggle. I am already completely at a loss as to where to begin the investigation. If anyone can give me a little hint or help, maybe I am missing something really important here, I would really appreciate your help.
Thank you!