Did you change router settings? Get a new router or modem? Did your ISP change something without your knowledge? These things can cause the game to start as if it is being started for the first time...But your files will still be there.....
I had this happen when verizon sent me a modem upgrade; once i got the modem up and running i changed the password and home wireless network name back to the previous setting and my game, both times, started as being started the first time.