password

My question is, that i have a win98 that was in a network, when i turn on the computer, the log on is requiered after I press cancel the system goes on then it comes the network password, the thing is that i don’t know the password, also the pc is not attach to the network now, how can i erase that pop up asking me the password, and if i try to press cancel, or double enter the sytem shut down
thanks all