programs opening on startup

sometimes when I turn on my macbook pro all the office programs are opening at the start-up although they were shut down and quitted before turning off the computer and they are not even in the list of programs to be open with the start-up.
anybody can advice ?

thanks

Are you using Lion? If so, do this:

Open System Preferences, General. Remove the check from the box that says:

"Restore windows when quitting............."

Exit System Preferences and reboot.