I forgot my password and can't access the alternative email. I have tried using password recovery software, but it's not able to recover my password.
You can reset your password using the "Forgot password?" wizard available on the Yahoo website. Access the link and use one of the options, then you will have the possibility to reset the password. If you have the password for your account, log-in on the mail interface then access the Account Settings and there will be the possibility to change the password.