Help me to update Hp Envy m6-k025dx to windows 8.1

I'm using HP envy m6-Ko25dx which comes with pre-installed windows 8 and I'm striving to update it to windows 8.1, I tried about 4 times but failed I update all the important updates from Microsoft and HP as well. Further I checked my laptop compatibility which is quite comfortable with windows 8.1.
The issue is I'm facing is common for many people who tried to update their system, I'm downloading windows 8.1 from windows store and up to 65% all goes fine but after restart some setting processed and then laptop screen display nothing totally black, finally I've to restore my previous version