Where is my eMAIL stored in my laptop?

Hello. I would like to know WHERE in my laptop is my downloaded MAIL, please. I need to reinstal Windows, and I can’t find my mail to back it up. Thank you.

Database location:
C:\Users%Current User%\AppData\Roaming\eM Client (Vista/Win7)
C:\Documents and Settings%Current User%\Application Data\eM Client (XP)

does eM Client stores email in the local computer or it leaves everything on the server (Gmail, or any other host)? 

Is it possible to choose if keep everything online or download locally?