Big mozilla problem

[i_will_learn_fl]

I was working on my comp 2day and i opened mozilla. Later mozilla had a problem and had to close. Next time I opened it it said which user should use it. I clicked on default and it said default was being used and so i created a new profile and now in this ne porfil all the bookmarks are gone everything is gone. I rly need some help. Can someone tell me how to switch back to the default user.PLZ