How can I reinstall and reset my Ubuntu just as if I've just installed it for the first time? I'm having issues, for example when I try to update it (I'm using Lubuntu) it does not let me do so and it says it's experiencing an internal error. I'm not sure about what to do:
Ign http://ppa.launchpad.net trusty/main Translation-en_US
Ign http://ppa.launchpad.net trusty/main Translation-en
Fetched 3,641 kB in 12s (284 kB/s)
W: Failed to fetch /openshot.developers/ppa/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch /openshot.developers/ppa/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
sudo apt-get update
via terminal and edit your question to copy paste the output. – JoKeR Jun 03 '15 at 22:10