I purchase a Lenovo laptop Z50-75 in July 2015 just before the Windows 10 upgrade. I updated my laptop with windows 10 as soon as I received my invitation to do so. Shortly after I started to get an error message "Thread stuck in device driver" and my laptop would reboot and work for a short time. Now I get the error message and the laptop continously reboots and is totally useless. What can I do about it constantly rebooting? It is inoperable.