I've been seeing this in the past 2 months. 3 so far. There appears to be a pattern. After a cold boot the computer seems to work for about 13 minutes then restarts on its own. After that, the amount of time it stays on seems to reduce more and more until it is rebooting even before windows loads. Also rebooting in safe mode. I am pulling my hair and mind out (not literally). No amount of research has helped so far. Malware scans have not helped. I am wary of system restore since the computer might reboot right in the middle of it, but I have done that for one of the computers, successfully, and that did not solve the problem. I have not specifically removed Windows updates, but the system restore would have done that for me right? Opened one of the computers that had this problem and blew out dust. Reseated and even swapped memory chips. My current specimen is having it's main board replaced today, by Lenovo. My fingers are crossed. Any ideas would be cool.