I'm fairly new to Ubuntu and while messing around with different things and trying out some shells, I've managed to mess my system up. Specifically I really messed up my GNOME session and can't get it to run really at all.
Is there a way to backup my apps but reinstall or just "restore" Ubuntu to its original condition? I had tons of updates installed, downloaded and setup my machine for Android development, and a few other things with a very slow internet connection.