changing password in main login.

Ok, i've been reading how to change passwords and such.. but I just need a simple answer..

I have 1 login to sign on upon start up... I NEED to get that password changed. I dont want to make a new login for the other person who uses my computer, its just my boyfriend... he has his own computer. but knows my password. and I just dont want him on it when i'm not home...after what I found today in the history :) so simple answer to a simple question.. how do I just change the initial login password for ubuntu...

which version of ubuntu are

which version of ubuntu are you running?
in karmic login and then click System-->Administration-->Users and Groups
highlight your username and click properties. there is a button on the properties tab "Change Password..."

I have ubuntu 8.04. I went

I have ubuntu 8.04. I went to change a password.. where I found the option.. still didn't change the password for the initial login.. so not sure what exactly it did!

if your not afraid of

if your not afraid of terminal you can open up a terminal and type passwd username
username being your login name. it will ask for current password and then new password and finally confirm password. now as always when in terminal it will not show the password when you type it.