So here I am sitting in a big pile of muck...over the last 2 days things have just been going from bad to worse with version of Ubuntu 12.10. So 2 days ago I was fiddling around with kismet and airmon-ng. I had added a bunch of libraries, I remember adding GTK+, Glib, Pango, etc. After restarting the other day my desktop opened fine but my background was changed to the default and none of my files on the desktop were visible and the top bar and side bar were not visible or functioning. The window managers were still working. I then tried reinstalling my nvidia drivers to see if that would change anything, it did not. Then after doing some searching online I found something that suggested I try deleting the file "libgtk-3.so.0". I deleted this and tried to restart the computer. Upon restart, I was greeted by a black screen with some writing saying something about -starting clamAV [OK] -problem with Apache Server could not verify correct...something... - checking battery state [ok]. After it gets to battery state it just stops and sits there indefinitely. So to sum, I cannot login to ubuntu because it just sits at this black screeen. If anyone has any idea as to what is going on and how to fix it please let me know. Thanks!
Ok, take a deep breath.
First let me get in the needed comment about deleting libraries. NEVER EVER EVER delete any library or program in the way you did. Always use apt-get or one of the gui front ends.
Now on to actual helping.
The problem your having is that gtk (the libraries that tell the computer how and where to draw buttons, windows, boxes etc.) has been deleted from your box. Therefor lightdm (the login screen) needs gtk to tell it where to draw it's boxes and it doesn't have it.
Because you deleted the file by hand, your package manager doesn't know that it's not there. To reinstall GTK try:
If you are never prompted with a login prompt (it will be text) you can press ctrl+alt+F1 to change to a text console. When entering your password it will not sow on the screen. Just type it as normal, and press enter.
Once you reinstall libgtk you need to fix your original problem. First I suggest creating a new user (from the text console) by typing
If it's just your settings then as your original user
If it's system wide, you probably messed up your libraries when you installed those libraries you mentioned above. If that is true, your best path to correction is to either uninstall the libraries if you kept track (assuming you installed them manually) or to backup your home directory and reinstall ubuntu. There are other ways, but they are very time consuming and not for someone new to linux.
Once your get gtk installed again it never hurts to do a