Basically you are asking how to hack into yahoo mail, which is impossible by todays standards, unless you are a really good hacker with a good hacker ring to help you out. I would suggest contacting yahoo directly if the mail is so important or signing up for a new one
I have the same problem I've contact Yahoo.com, but they told me that my mail account is no longer on my name , saw the hacker change all my data.
You should have a security question. When you click I forgot my password it should ask you that. Answer it then if will change your password to something new and tell you what it is. Then you go on with that password from there you should be able to change it to something you know.
my yahoo account got hacked by some one.i remembered my secondary email but it is giving your password can not reset online(9001).i will be helpful if any one can give me great idea.