Sorry, the application add-apt-repository has stopped unexpectedly

If you just need to get out of such annoying crash reports, do the following:

In a terminal run sudo apt-get install gksu to install gksu

Now run gksu gedit /etc/default/apport Here make enabled=0 and save the file.

From next login onwards you will not get such messages.

HOW TO CHECK YOUR UBUNTU VERSION

Check version via terminal
Alternatively, you can find information about the version through the terminal as well. For that, simply type in the following:
"lsb_release --a".

How to Find Serail No of Laptop with CMD

To find Serial no of Laptop just open CMD and type

wmic bios get serialnumber