Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
Since the PC gives us the best chance of recovery, lets discuss the PC first.
The email account on your pc that lost all the messages. Who was that email account with?
Gmail, aol, yahoo, hotmail, etc?
Also, how did you access your email on the pc.. Did you use a program such as windows mail, thunderbird, Outlook 2010, etc ?
Thank you in advance for your response,