Dropbox installation broke my software index (Ubuntu 12.04)

I'm running Ubuntu 12.04 (x32) on a desktop computer. I tried installing Dropbox from the Ubuntu Software Center and it got stuck almost at the end. So I tried to close the software center and restart. When I opened the Software Center Again I could see Dropbox installed, but I knew it wasn't ok because it hasn't finished installing so I clicked on Remove, and it also got stuck close to the end.

So i searched the web and ran :

   sudo apt-get remove dropbox; rm -rvf ~/.dropbox ~/.dropbox-dist
   E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
   E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

I think it's the Ubuntu Software Center... but I don't know how to kill that process safely. So I found the PackageManagerTroubleshootingProcedure here

   https://help.ubuntu.com/community/PackageManagerTroubleshootingProcedure

and ran the commands with the following results:

//------------------------------------------------------------------------------------------------------------------------

sudo apt-get install -f
E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?
sergio@sergio-All-Series:~$ ubuntu-support-status
Support status summary of 'sergio-All-Series':

You have 105 packages (4.2%) supported until October 2013 (18m)
You have 58 packages (2.3%) supported until January 2016 (18m)
You have 1601 packages (64.7%) supported until April 2017 (5y)

You have 1 packages (0.0%) that can not/no-longer be downloaded
You have 708 packages (28.6%) that are unsupported

Your current Hardware Enablement Stack (HWE) is going out of support
on 08/07/2014. After this date security updates for critical parts (kernel
and graphics stack) of your system will no longer be available.

For more information, please see:
http://wiki.ubuntu.com/1204_HWE_EOL

To upgrade to a supported (or longer supported) configuration:

* Upgrade from Ubuntu 12.04 LTS to Ubuntu 14.04 LTS by running:
sudo do-release-upgrade

OR

* Install a newer HWE version by running:
sudo apt-get install linux-generic-lts-trusty libgl1-mesa-glx-lts-trusty xserver-xorg-lts-trusty linux-image-generic-lts-trusty

and reboot your system.

Run with --show-unsupported, --show-supported or --show-all to see more details
sergio@sergio-All-Series:~$
sergio@sergio-All-Series:~$ cat /etc/dpkg/dpkg.cfg.d/multiarch
cat: /etc/dpkg/dpkg.cfg.d/multiarch: No such file or directory
sergio@sergio-All-Series:~$ ubuntu-support-status
Support status summary of 'sergio-All-Series':

You have 105 packages (4.2%) supported until October 2013 (18m)
You have 58 packages (2.3%) supported until January 2016 (18m)
You have 1601 packages (64.7%) supported until April 2017 (5y)

You have 1 packages (0.0%) that can not/no-longer be downloaded
You have 708 packages (28.6%) that are unsupported

Your current Hardware Enablement Stack (HWE) is going out of support
on 08/07/2014. After this date security updates for critical parts (kernel
and graphics stack) of your system will no longer be available.

For more information, please see:
http://wiki.ubuntu.com/1204_HWE_EOL

To upgrade to a supported (or longer supported) configuration:

* Upgrade from Ubuntu 12.04 LTS to Ubuntu 14.04 LTS by running:
sudo do-release-upgrade

OR

* Install a newer HWE version by running:
sudo apt-get install linux-generic-lts-trusty libgl1-mesa-glx-lts-trusty xserver-xorg-lts-trusty linux-image-generic-lts-trusty

and reboot your system.

Run with --show-unsupported, --show-supported or --show-all to see more details
sergio@sergio-All-Series:~$ cat /etc/dpkg/dpkg.cfg.d/multiarch
cat: /etc/dpkg/dpkg.cfg.d/multiarch: No such file or directory
sergio@sergio-All-Series:~$ dpkg --print-foreign-architectures

sergio@sergio-All-Series:~$ sudo grep -R proxy /etc/apt/*
sergio@sergio-All-Series:~$ grep proxy /etc/environment
sergio@sergio-All-Series:~$ echo $http_proxy

sergio@sergio-All-Series:~$ echo $ftp_proxy

sergio@sergio-All-Series:~$ grep proxy /etc/bash.bashrc
sergio@sergio-All-Series:~$ grep proxy ~/.bashrc
sergio@sergio-All-Series:~$ cat /etc/apt/apt.conf
cat: /etc/apt/apt.conf: No such file or directory
sergio@sergio-All-Series:~$ sudo fuser -vvv /var/lib/dpkg/lock
                     USER PID ACCESS COMMAND
/var/lib/dpkg/lock: root 2230 F.... dpkg
sergio@sergio-All-Series:~$ sudo fuser -vvv /var/cache/apt/archives/lock
                     USER PID ACCESS COMMAND
/var/cache/apt/archives/lock:
                     root 2224 F.... aptd
sergio@sergio-All-Series:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=12.04
DISTRIB_CODENAME=precise
DISTRIB_DESCRIPTION="Ubuntu 12.04.4 LTS"
sergio@sergio-All-Series:~$ uname -a
Linux sergio-All-Series 3.11.0-24-generic #42~precise1-Ubuntu SMP Fri Jul 4 21:23:53 UTC 2014 i686 i686 i386 GNU/Linux
sergio@sergio-All-Series:~$ sudo rm /var/lib/apt/lists/lock
sergio@sergio-All-Series:~$ sudo rm /var/cache/apt/archives/lock
sergio@sergio-All-Series:~$ sudo rm /var/lib/dpkg/lock
sergio@sergio-All-Series:~$ sudo cp -arf /var/lib/dpkg /var/lib/dpkg.backup
sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad
sergio@sergio-All-Series:~$ sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad
sergio@sergio-All-Series:~$ sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad
mv: cannot stat `/var/lib/dpkg/status': No such file or directory
sergio@sergio-All-Series:~$ sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad
mv: cannot stat `/var/lib/dpkg/status': No such file or directory
sergio@sergio-All-Series:~$ sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status || sudo cp /var/backups/apt.extended_states.0 /var/lib/dpkg/status
sergio@sergio-All-Series:~$ sudo mv /var/lib/dpkg/available /var/lib/dpkg/available-bad
sergio@sergio-All-Series:~$ sudo cp /var/lib/dpkg/available-old /var/lib/dpkg/available
sergio@sergio-All-Series:~$ sudo rm -rf /var/lib/dpkg/updates/*
sergio@sergio-All-Series:~$ sudo rm -rf /var/lib/apt/lists
sergio@sergio-All-Series:~$ sudo rm /var/cache/apt/*.bin
sergio@sergio-All-Series:~$ sudo mkdir /var/lib/apt/lists
sergio@sergio-All-Series:~$ sudo mkdir /var/lib/apt/lists/partial
sergio@sergio-All-Series:~$ LANG=C;sudo apt-get clean
sergio@sergio-All-Series:~$ LANG=C;sudo apt-get autoclean
Reading package lists... Done
Building dependency tree
Reading state information... Done
sergio@sergio-All-Series:~$ LANG=C;sudo apt-get --purge autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up nautilus-dropbox (0.7.1-2) ...

Dropbox is the easiest way to share and store your files online. Want to learn more? Head to http://www.dropbox.com/

Downloading Dropbox... 100%

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And it's stuck there...
Hope this is enough information to ask any help =)

Thank you!

Sergio MP