After reinstall of OS on iBook G4, getting an AirPort error when trying to connect to wireless network

Thanks for your response, but the initial problem is that I'm still stuck in the set-up process. I can't move past this screen to get to anything else unless I can get it to accept my wireless network password, or I suppose I could go back one screen to the "How Do You Connect?" screen and select "My computer does not connect to the Internet." I presume that might get me past this set-up phase into an area where I could futz around with settings. But I was concerned about disabling something I couldn't fix later (me, not a techie!) by selecting that. What's the consensus? Should I just do that so I can get out of the set-up process? Will I be able to reactivate my AirPort once I'm just in operating mode? I really should be more technically proficient than this...

Duh. Finally remembered that I do actually have a wired connection I can use. So I selected connect via ethernet and was able to move past the set-up stage. Will now peruse the advice on changing settings and get back to you if I'm unable to solve the problem. Thanks!

Didn't even think to update the OS or use software update. Feeling kinda dumb about that. So, that was helpful. However, it didn't fix the problem. Still getting AirPort error when trying to join the wireless network. I know it's the right network, and I know it's the right password (have connected both my smartphone and newer laptop using that password tonight). Very frustrated and only have wired connection in one room of the house - of course not the room where the laptop is going to live!