You have to type the password exactly the way you did when you signed up.
Don't worry, use the lost password feature and reset your password.
Remember do NOT use words as passwords and mix it up a little. Mix number and letters and caps together, but make it so you'll remember it.
Hope this helps.
Rick
Ihave signed up for Yahoo mail. It keeps asking for the id and password. inspite of typing the right id and pw it says password is invalid. Is there something i need to know about yahoo? Please help.
Guru

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic