administrator password

From: cmar1 (cmar1_at_optonline.net)
Date: 04/30/03 

Date: Tue, 29 Apr 2003 20:34:14 -0700

I log on with user name and no password, but I'm trying to
install software which requires administrator log on. The
problem is I forgot the password and cannot access
administrator, does anyone know how I can do this.
PLEASE HELP!!

thanks