I am still suffering with this problem too. I read on another thread that checking/unchecking the options in Power Options (Choose what the power button does, Change settings that are currently unavailable then change the settings at the bottom) had an effect for some, so maybe worth trying. Mine were originally set with Sleep and Restart checked and Hibernate unchecked. I now have all three checked.
However, this did not work for me so I contacted Microsoft support by chat. They said that I should try to do a Refresh or a Reset. Since this would mean for a Refresh I would need to reinstall all my applications, and for a Reset all applications and files, neither are steps that I would want to rush into. If the problem till remained, then it would be a hardware fault.
However, quite by coincidence, I have recently been working without my keyboard attached, and for four days had no problems. Yesterday I attached the keyboard and PROBLEM. So, I am now trying without the keyboard again. It would be really interesting to know if you have the same.
(I have had problems in the past when using my keyboard that it hangs and I have to detach and reattach. Apparently this also maybe a hardware problem with the keyboard..... possibly the root cause?)
Please let me know how you get on.