Can't check for/download updates

Question

I've noticed I can't check for new updates, neither via terminal nor update manager. For example, update manager throws error saying something like "failed to download repository information. check your internet connection". Details are the following:

W:Failed to fetch http://ppa.launchpad.net/slicer/ppa/ubuntu/dists/precise/main/source/Sources  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/slicer/ppa/ubuntu/dists/precise/main/binary-i386/Packages  404  Not Found
, E:Some index files failed to download. They have been ignored, or old ones used instead.

I did a bit of googling, still couldn't find any solution :/

Answer 1

You have added some PPA to your system's package management which isn't available anymore. Try this to remove the PPA and the packages installed from it.