I have the same problem! It randomly shuts down after very brief periods on inactivity e.g. after the time it takes to read a few paragraphs on the screen etc. Often when this happen is will not power back on. Some times If I hold down the power button
for 10 seconds, then release, then push the power button once, it starts up with the Microsoft logo.... but sometimes it doesn't respond/turn on at all, and I have to wait 10mins and try it (reboot) again, then it will work. Happens despite the sleep and shutdown
settings all set to 1hr or more. Happens despite battery being at least 60% or more. I've only had this S7 since the 5th May, and it was fine for the first 10 days... then from the 16th May it's being randomly shutting down frequently!