Hi Carina,
In the box that you use to log into Yahoo at the bottom of the box click on the link "Forgot your password?". This will take you to the next page. Fill in the information and click on the "Get New Password" button. Yahoo will generate a new password for you and that should get you into your account. Then you can go to your account and change the password to whatever you want to use if you want to do that. This should take care of the problem, if it doesn't work let me know.

Eva