dont remember password

i have a workstation with win 98 that is remembering his password at logon, and i do not want it to remember, how can i go and force it to prompt for network login? it does not have any profiles for separate users and there is no *.pwl file that you normally have it just ahutomatically logons at bootup..he said he put a check in the remember password when he entered in his password…
thanks