Airport Base Station: How to delete old config/pref files, reset, and start fresh?

[laloula]

Recently had my Comcast cable modem switched out because was not getting service. Decided to retire old Linksys wired router and just go through Airport base station (old model, b/g). But now, can't get connected at all. Doesn't show up in Admin Utility. Tried fooling around with settings, but do not totally understand all of them. Manual doesn't help. I understand using the reset button, but creating a default config doesn't help, still not connecting to internet through airport. Now I'd like to delete all config and pref files and reset the Airport to start completely fresh, but can't figure out where these files live. Can't find a pw I set up in keychain, either. How do I "start fresh" and reconfigure all over again from scratch?