Whenever I try to update my computer by opening the Update Manager I get this problem and it just closes. Can someone help me?
W:GPG error: http:/packages.medibuntu.org quantal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2EBC26B60C5A2783,
W:Failed to fetch http:/ppa.launchpad.net/ferramroberto/gsharkdown/ubuntu/dists/quantal/main/source/Sources 404 Not Found
W:Failed to fetch http://ppa.launchpad.net/ferramroberto/gsharkdown/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found
E:Some index files failed to download. They have been ignored, or old ones used instead.
quantal
directory on that server. If you are on 12.10 you might want to switch to theprecise
PPA. – douggro May 01 '13 at 06:02