You shall need :-
- An Linux operating system -(Ubuntu ,Fedora or anything .. )
- Direct access to the system, ie you need to restart it alright.
- The Recovery mode enabled in the GRUB is not a necessity.
The steps :-
- So, the vector is the GRUB boot loader, we see just after booting on our system :-
- Here, select the first option , and press 'e' as it says to edit.(Ubuntu,with LINUX )