Thanks a lot guys, that solved the problem !

What were you doing when that happened? Were you messing with partitions? Did you add any software from other repositories?
I was tweaking the preferences & settings. In fact I was changing the theme when I was logged out. I did not change any partitions or add/edit any packages from the ...

While using Salix 13.1 (XFCE) which I installed 2 days ago, I was suddenly taken to log in window even though I hadn't logged out. When I tried to login again, I was unable go to desktop because after a brief glimpse of terminal which shows "starting X11 server" in green with darkstar login prompt ...