Try F7.

OK my EMail and contact is back it isn't the same format but I can deal with that. But it doesn't display or show my wife's EMail account

now my wifes email is gone.it asked for password .how do I find out that?

Email providers supply passwords, Thunderbird only keeps a list that you provide. The usual cause of a sudden request for a password is the anti virus program messing up, but it can also be caused by changes in connection settings required by the mail provider.

To that end, what mail provider and what anti virus do you use?