Ibook Won't Autoconnect to Wifi Using Osx 10.4.2


I'm using a 900MHz G3 iBook with 640MB RAM and connecting to wifi via an Airport Extreme running v5.6 firmware. When I was using Panther, the iBook would automatically connect to my home network (128bit WEP). However, after upgrading to Tiger (and then 10.4.1 and then 10.4.2), it's necessary to click on the little signal icon at the top of the screen and manually choose my network. I'm using the "automatic" network setting...nothing automatic about it, as far as I can see. I tried setting up another profile specifying just this network...but no difference. Someone in an earlier post suggested deleting the keychain. Didn't work for me. Any thoughts? Thanks!!!!