Hi, I'm Robert and I'll be helping you with your computer question.
i can help and sometimes i am succesful
but it all comes down to whether you have a way to prove to the yahoo computer that you own the account
that usually means having access to the phone number or alternate email that you originally set up with the account.
if you don't have either it is very difficult . about the only way to do it is get the company to reopen your old email account or hope somebody has your old phone number and if you call them they will be nice enough to give you the code yahoo sends.