Error opening the cache

The error message is:

E:Unable to parse package file /var/lib/apt/lists/ro.archive.ubuntu.com_ubuntu_dists_groovy-updates_In release(1),E:The package lists or status file could not be parsed or opened.

I can't update anything. I opened the terminal:

fane@fane-desktop:~$ apt-get
apt 2.1.10ubuntu0.2 (amd64)
Usage: apt-get [options] command
       apt-get [options] install|remove pkg1 [pkg2 ...]
       apt-get [options] source pkg1 [pkg2 ...]

apt-get is a command line interface for retrieval of packages
and information about them from authenticated sources and
for installation, upgrade and removal of packages together
with their dependencies.

Most used commands:
  update - Retrieve new lists of packages
  upgrade - Perform an upgrade
  install - Install new packages (pkg is libc6 not libc6.deb)
  reinstall - Reinstall packages (pkg is libc6 not libc6.deb)
  remove - Remove packages
  purge - Remove packages and config files
  autoremove - Remove automatically all unused packages
  dist-upgrade - Distribution upgrade, see apt-get(8)
  dselect-upgrade - Follow dselect selections
  build-dep - Configure build-dependencies for source packages
  satisfy - Satisfy dependency strings
  clean - Erase downloaded archive files
  autoclean - Erase old downloaded archive files
  check - Verify that there are no broken dependencies
  source - Download source archives
  download - Download the binary package into the current directory
  changelog - Download and display the changelog for the given package

See apt-get(8) for more information about the available commands.
Configuration options and syntax is detailed in apt.conf(5).
Information about how to configure sources can be found in sources.list(5).
Package and version choices can be expressed via apt_preferences(5).
Security details are available in apt-secure(8).
                                        This APT has Super Cow Powers.
fane@fane-desktop:~$ apt-get update
Reading package lists... Error!
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
E: Unable to parse package file /var/lib/apt/lists/ro.archive.ubuntu.com_ubuntu_dists_groovy-updates_InRelease (1)
E: The package lists or status file could not be parsed or opened.

You have to open terminal, then execute the following commands to repair APT:

sudo rm -v /var/lib/dpkg/lock* /var/cache/apt/archives/lock
sudo rm -vrf /var/lib/apt/lists/*

Then update package lists using normal update command:

sudo apt-get update

Finally install upgraded package versions using below command:

sudo apt-get upgrade

Also please note that all above commands use sudo for getting root privileges to run system maintenance tasks. You can't run such tasks using ordinary user rights.