If one account is hacked, other accounts or services linked with it are in the danger zone. The hackers work on finding these links and getting control of all the accounts a user has on online space. So, protecting your logins is highly recommended especially if you use same password for different accounts (which is not at all a smart idea.) Use strong combination for creating a unique password. The password should be difficult to guess and at the same time easy to remember for you. This will protect other accounts from the attack. If you want to recover your account and think that the process is complex, contact yahoo customer care by email support for assistance.