iBook G4 Not Remembering Password

I've just done a clean install of Leopard on a friend's iBook G4, but having given it back to them and helped them connect to their wireless router, I've just been told that after the laptop is shut down, it "forgets" it's been connected and has to be manually reconnected (with the respective wi-fi password needing to be typed each time on startup).

They tell me the box is ticked to "remember this network" or similar.

Any ideas what this may be or what to check?

No-one got a clue?

Could it be the wireless driver??? (how do I check if it has the very latest driver installed?)

Could it be a permissions issue?

Disappointed with no replies whatsoever to my question, but for reference, this problem was caused seemingly by me having the laptop connected to my wireless router during the clean install, and then it was connected to my friend's wireless router, and their router was listed below mine in the advanced settings which seemed to confuse the O/S!

By simply deleting my wireless network from the list and having my friend's as the only one solved the issue.

I would have expected Mac O/S to be more intelligent....this wouldn't have been an issue on Windows.