I think you might be confusing the password for access to the router's settings with the security key for wireless access to the connection. Admin is frequently the login for the former with password as the password but the WEP, WPA or WPA2 security key is something you can only find once you've been in to the settings.
I have attempted to change my password, but it still takes admin. I have a befcmu10 modem and 802.11b router. I can get to password screen and I have enter a new one, hit apply. I logged on from a computer with a wireless adapter, picked the network and when it asked for the wep, I entered the new password. didn't take it. I tried admin, bingo. I'm probably being a knucklehead, but what am I doing wrong? THX