how did you apply the paste? You should have used no more than a grain of rice sized blob and then either spread with a bank card or squished with the heatsink when putting it on. Also did you remove all the old paste properly?
Failing that check the heatsink is properly on the CPU
Yes i have applied the paste evenly using a bank card provided with the paste (cooler master) and only used a grain of rice sized blob as u said. Yes the old paste was properly removed. Thanks for your reply.