Laptop keys not working after display card repair

I recently gave my laptop for repair of display card as there was no image on the laptop screen.

That problem has been solved but after the repair many keys are not working like Q, W, E, R, U, I, O, P. (i.e most of the alphabets of the first line )

Can the forum tell me the cause of this problem ? Has it got something to do with the recent repair of display card. Has the laptop not been closed properly after it was opened for the repair of display card

Kindly help?