That threw up this error:
What should I do? It seems to me that the problems lie with many if not all of the files in the /var/lib/apt/lists directory. Is it safe to delete all of them? And should I try to? And I don't know what the GPG error is at all...
Reading package lists... Error!
W: GPG error: http://gb.archive.ubuntu.com quantal Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <firstname.lastname@example.org>
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_quantal_main_i18n_Translation-en%5fGB
E: The package lists or status file could not be parsed or opened.
EDIT: Software Updater just popped up with the same errors as in my first post and said that it was an 'unresolvable error'... I hope that it can be resolved somehow!