i cannot open my mail.app…

When i opened my computer this morning i clicked on my apple mail program and what i got was the welcome to Mail message with the continue buttom for importing mail messages and the cancel button. if i press either button the app just quits.

Has anybody out there had this problem before and if so what did you do?

I am not bothered to much about the app it'self as at the end of the day i can reinstall but i have a lot of emails that i need to access and I cannot find any data on my computer at all so my greatest concern is that i've lost all my correspondence.

I would appreciate any help and information anyone can give me.

Cheers