The Lenovo M91P refurbished computer from Skytech keeps shutting down. Skytech technical support advised me to send in the HDD for exchange, which I did (at my expense). Still didn't work. Skytech then sent me Windows reinstallation instructions. Despite quite a few tries, that did not work either. Amazon advised me to ask Skytech how to return it, as it is now outside of Amazon's 30-day return window. I have written Skytech to get return instructions. If a return is successful, I will revise this review.