Lenovo — Lenovo Ideapad z580 fake os

Address:

East Godavari, Andhra Pradesh

Hello, I bought my around may 2012. I worked fine for 1 year and sundenly os crashed, when I went to the dealer I found product label missing for my laptop which was not found from beginning . Dealer managed me again saying that he posted complaint and got original key . Again after one now my windows is reporting "this is not genuine" plz help me.