I am working on Debian Lenny 5.01, later installed wifi driver for my laptop from official debian repository...

when i login to my system the wifi get connected (both auto/manually) to the wifi router. but after first connection when i disconnect it and then reconnect it back then it dont connects to the router (both same/different)...

same problem remains when i login to my system then switch on the wifi button the network manager donot find any wifi signals from any of the routers.

some times it happens that the neworkmanager is showing the it is connecting to "null" but none of the two LEDs of the network manager icon are elighted...

what should i do to resolve this strange behaviour..

That's a scripting problem. It sounds like the first connection isn't closing off when you log out. I personally would like _the_box_ to log on when I log on, and stay there. Tastes differ. Fiddle your /etc/rc.d/rc?.d links accordinglly. Put in Knn link if you want something killed. The link should point at the ../init.d/script