A day back everything was fine when using the Software Center. The problem started after attempting to install the app named 'Shutter' (app for taking screenshots) yeasterday. I started the Install then went to watch a movie came back to my PC 3hrs later it was showing 'Applying Changes' it was odd as the software was just 15MB and should have got over. Later on... after 2 hours of staring 'Applying Changes' I couldn't wait no more and had to shutdown the PC. Today morning when I opened the Software Center the 'Applying Changes' was still there, I cannot install any other software using the center as it says 'waiting' for the Shutter App to finish and I want to stop the installing but just can't as there is no X or Cancel button to stop it.
Using the Terminal I've tried >>

mohd_arafat_hossain@TUD:~$ sudo killall -9 apt-get

[sudo] password for mohd_arafat_hossain: 

apt-get: no process found

mohd_arafat_hossain@TUD:~$ sudo dpkg --configure -a

dpkg: error: dpkg status database is locked by another process

mohd_arafat_hossain@TUD:~$ 

What am I supposed to do now?