To recover lost deleted emails in Yahoo Mail: 1. Log into Yahoo Mail and go to the Trash folder. Select any messages to undelete and click "Move" to restore them to the Inbox or another folder. 2. You can also drag and drop emails directly from the Trash folder to recover them. To access an old Yahoo account created with Facebook or Google: 1. Go to the Sign-in Helper and enter your Facebook or Google ID in the Yahoo ID field. 2. Follow directions to sign in, then create a new Yahoo password once successfully logged in.