If some other activity is performed after the shut down, of Explorer this doesn't occur. Shut Down Bug. This started a few months ago. Most of the time it reboots and starts over. On my laptop, the suspend mode now results in a GPF error message and can not be recovered.
Screen Saver Bug.
Also on the laptop, the Microsoft internal screen saver results in a GPF error, and if you turn off the screen saver the screen saver comes on anyway. I demonstrated the system crashing from the screen saver in front of an audience of 500 people once for a laugh. I got a huge laugh and a round of applause. So this may actually be a feature. Scan Disk Bug.