Sony Vaio Laptop Keyboard Keys not working again and again

Hello,


I have purchased one Sony Laptop on 06.09.2013 and in 02.2014 the laqptop's keys not worked properly (Some of Keys). After approaching of Sony Care they Replaced with new Key Board. Again 3 months after the New Keyboard's Keys were not working.

No. of Keys in my Keyboard not functioning since last 3 days. How to fix this again and again if the problems occus.