This question already has an answer here:
My software Updater is no longer working. the computer tells me i need to check from updates, it shows a red triangle symbol that if you click it give me an option to show updates but when i do the software updater either doesn't open or takes an extrodinary long time to do so. When i finally do get it open it either says that the software is update or checks for updates and fails to download repositories. I'm not very knowledgeable about linux or ubuntu yet so if i could get some help that would be great.
these are the last few lines of what the terminal outputed:
W: Failed to fetch http://ppa.launchpad.net/deluge-team/ppa/ubuntu/dists/raring/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ppa.launchpad.net/deluge-team/ppa/ubuntu/dists/raring/main/binary-i386/Packages 404 Not Found E: Some index files failed to download. They have been ignored, or old ones used instead.