Win keeps sending me back to the log in screen when unattended?

If I leave my computer for more than 30 min or so, I come back and I am at the log in screen. Applications that where running have stopped.
Sleep and hibernate are disabled, and screen timeout has been set to 5 hours.
This started about a month ago, and after 2 weeks was back to normal and then a week ago started doing it again.

Any thoughts?

edit: after looking at event viewer, I see this line following each restart:
The computer has rebooted from a bugcheck. The bugcheck was: 0x0000007e (0xffffffffc0000005, 0xfffff806886c15b0, 0xffffbb80f6c657f8, 0xffffbb80f6c65020). A dump was saved in: C:\WINDOWS\MEMORY.DMP. Report Id: c37fabf6-f681-4d14-b0cd-32787a74b441.
Thanks,
Gene

Hi Scrabblegod, welcome to 10F! :)

The bugcheck 0x0000007e refers to: STOP 0x0000007E: SYSTEM_THREAD_EXCEPTION_NOT_HANDLED; Its usual causes are: Insufficient disk space, Device driver, Video card, BIOS, Breakpoint with no debugger attached, Hardware incompatibility, Faulty system service, Memory, 3rd party remote control.
Read through the carrona link especially below the KB article links starting at Cause and Resolving the Problem to see if you recognize anything that might relate to your situation.

After looking at your system specs the only thing I could suggest is checking for a new(er) driver for the 560ti GPU.

• I would of drilled down for your driver here: Drivers | GeForce, but you don't list what bit rate (32 or 64) your version of win 10 is.
• With this being a 560 it makes me wonder if your 10 machine is an upgrade from win7 or 8.
• You could try doing a re-install of the present 560 driver, sometimes that helps if the driver becomes corrupted somehow.
• When was the last time you restarted this machine, preformed a disk cleanup?
• There are some missing entries in your system specs that would provide more information, you could learn more if you used this to finish filling in your specs.
• Use this DM Log Collector to obtain more comprehensive information relating to you problem, then upload the file that is created to this thread in your next reply, we may have to ask the Mods to move your thread to the BSOD Crashes and Debugging forum to get more eyes on your problem.