If you find that your computer keeps coming out of hibernation or sleep by itself, it could be due to wake on lan been enabled.
This generic method of opening the Device Manager should work with most versions of Windows.
Click on Start
and type in device manager in the Type here to search box, then click on Device Manager
Expand Network adapters and right-click on the one you want to change the setting for
Select Properties from the context menu. If you are unsure of which network adapter to expand, normally, look for Realtek Lan or Wireless network adapters.
Here you will find a Allow this device to wake up the computer option.
Uncheck the box to disable it
Optionally, you can leave it enabled and check the option Only allow a magic packet to wake up the computer which will prevent everything except Wake-On-Lan packets from waking up your machine.
