Recently I did installed "dconfeditor" in my Elementary OS. I restarted my Computer and log-in and see all the beautiful look of Elementary OS has gone. I really no idea why this happened to me, So, I have no information other than this. Please tell me what can I do to restore that old theme in my Elementary OS.
Here are my screenshots:-
Before->


After->

I had the same problem and the solution that I found was to re-install the elementary-desktop
sudo apt-get purge elementary-desktop sudo apt-get install elementary-desktop
This is definitely a problem with the GTK themes. You should be able to fix this by installing lxappearance which is a program to change GTK themes and icon sets etc. and change back to the standard elementary theme.
I had the same problem, you need to install "elementary-theme" from the software center
