infact I installed i3wm in my freya.
after update, I my freya freezed after login to pantheon session. I could only login into i3wm session
So I just tried to uninstall and reinstall gala and wingpanel from i3wm using command sudo apt-get uninstall gala and similar for other
Problem with the freya was like whenever I login, wingpanel only showed the slingshot and search indicator at the beginning and later other indicators were shown but I couldnot access the indicators and my wifi used to get disconnected
little time later the whole system freezes and I had to hardreset the laptop
