Login to your account, open up a terminal window, type yppasswd , and hit Return. You will then be prompted for you OLD password first. I forgot my password. The Caps Lock is probably on. Turn it off.
Passwords are case sensitive.
The best passwords rhyme with orange. No, but seriously folks, passwords must be 6-8 characters long and contain a mix of letters and numbers or punctuation. Names of people or places. Such passwords will be guessed in a few minutes by password guessing programs, even when combined with other characters.