Asus laptop keyboard few keys not working

Are some or all of your laptop keyboard keys not working? Know from our experts what might be the problem and how to solve this.

I have an Asus S430U laptop purchased a year ago but recently it has run into a problem with its keyboard keys. Few keys like Left Shift and Ctrl stopped working, so I mapped the keys to other keys , but later on, the Enter key, Right Shift a well as a full stop and comma keys and a few more stopped working.
I looked for keyboard replacement but the same is also not available locally or online.

Is this a software issue or hardware issue? Should I look for a replacement or not?
Is there any place where I can get the keyboard for Asus notebook model S430U?

Editor: This has been solved here - Two keyboard letters 'A' and 'C' are not working in my laptop