No mail in my Thunderbird this morning and no active profile

Hi! Started Thunderbird this morning and the program needed an email account. I backed up my profile, configured my account and try to import my old profile content. This didn´t work and then I tryed copying the files from my old profile and this worked for some of my mail but no all off them. Why dosn´t import function. Why whas my account and profile gone. And how do I get back my mail content??? Med vänlig hälsning Olof