Brahim, just now only read the last post about setting everything back to default. It went through my head that Mint might not be default, and in that case one would need the extension FEBE (which I find very useful together with CLEO) to save one's preferences before setting everything back to default, just in case. Anyway it always helps to be able to save one's preferences. Have also saved browser history, usernames and passwords etc.
Release: Linux Mint 16 "petra"
Edition: Cinnamon 32-bit
Linux mint 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:12:00 UTC 2013 i686 athlon i686 GNU/Linux