I already checked for a possible answer to my question, but, how to fix this since my details are different from the other people here. Here's my error information on Software Updater:
[W:Failed to fetch http://linux.dropbox.com/ubuntu/dists/quantal/main/binary-amd64/Packages 404 Not Found [IP: 188.8.131.52 80] , W:Failed to fetch http://linux.dropbox.com/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found [IP: 184.108.40.206 80] , E:Some index files failed to download. They have been ignored, or old ones used instead.]
Any advise would be great. Thanks!