You have boot CD
's that help you erase the admin password and change it to something you like. I believe that software came also on floppy as well.
Besides that, when that system starts and it shows all available user accounts (fast login screen) hit CTRL+ALT+DEL a few times for showing the administrator account. Works like a charm. If she knows that password she can log in and change the password for her normal account. Saves a reformat. And if she doesn't, use the trick with the floppy or CD.
EDIT: Darn, PhilB beat me to it