Recently, my ubuntustudio 12.04 crashed and started offering me only one of the usual 4 panels. Also, every open application stopped having a close/minimize/maximize panel above it and the whole desktop looked jumbled, so i reviewed the problem and considered it to be one of uncleared session cache. i searched online and found a solution that said to remove files contained in /usr/share/xsessions/ via terminal. i delightedly deleted the files (been a Newbie&Naive!) and to my alarm after restart, i couldn't login to my desktop. This is the root of my problems, please help.