Is Warranty Denial Legal?

Question

Law in IT

I bought myself a Lenovo z50-70 laptop, the laptop at home did not turn on the lenovo splash screen and then a black screen, recovery too. I installed my os (windows 8.1 pro) . I checked the hdd for errors and it showed bad sectors, because of this, the computer periodically hung. I came to the service center, they said without the original Windows, the guarantee disappears (initially, Windows did not load the black screen). Of course, I read the guarantee, it is given for hardware parts and nothing is said about changing the OS. What to do in this case. Wrote a complaint. By the way, sellers are clearly confusing returns and guarantees, I demand goods without scratches. It takes place in Kazakhstan.

Answer 1

Have you checked in the store? Everything was fine?
1. Immediately it was necessary to return to the seller. Why bother??? Equipment is guaranteed.
2. Someone somewhere dropped / hit the included laptop. So it was not loaded, and BEDs appeared on the disk.
Have you shown the paper?
But for the traces of impact and J-Shock in smart HDD, they may well refuse a guarantee.