Shift key is not operated correctly on dell vostro 5470

Hi all,

I'm bought laptop dell vostrol 5470 in Aug 2014. My laptop use windows 8.1 64 bit.

Recently, I have a problem with my keyboard.

- when I press shift key left, my lappop is displayed letter 'SFJL' or 'SFJLk' on Microsoft  Office 

- when i press shift key right, my lapptop is turned on Caps lock

I have connected with another key board [key board for desktop]. It is not operated.

I have opened soft key board and click shift button [left/right]. It's operated normally

I can not input some letter such as shift + 2 = @, shift + 3 = #... 

So what happen with my key board, and How can I repair it.

I need your help please.

best wish for you.