W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/source/Sources Hash Sum mismatch
W: Failed to fetch http://ppa.launchpad.net/ubuntu-vn/ppa/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/ubuntu-vn/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.
W: Failed to fetch http:// archive. ubuntu. com/ubuntu/ dists/trusty- updates/ main/source/ Sources Hash Sum mismatch
W: Failed to fetch http:// ppa.launchpad. net/ubuntu- vn/ppa/ ubuntu/ dists/trusty/ main/binary- amd64/Packages 404 Not Found
W: Failed to fetch http:// ppa.launchpad. net/ubuntu- vn/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.