Click the cancel button and when the PC is done booting, do a find on:
*.pwl         and delete the one with your friend's user name (mine is
ron.pwl).  Then reboot and when the sign on screen appears, enter the same
user name and a new password.  If the user doesn't want to logon at each
boot, enter a blank password.

Blank Password:  Go to control panel, network, primary network logon and
select Windows Logon.  Go to control panel, passwords, user profiles and
ensure the "all user's" box is marked.  If you have a password established,
go to control panel, passwords, change windows password, type the password
in the old box, leave the rest blank and OK your way out.  If you have
forgotten your password, delete the .pwl file with your user name (mine is
ron.pwl); however, be aware that you will lose all passwords stored in the
.pwl file.  If you do not have a password established or have deleted the
.pwl file, when the W95/98 logon screen appears at boot, type a user name
only and hit OK.  If the logon screen continues to appear and you have Tweak
UI installed, go to the Paranoia tab and remove the mark from "clear last
user."