How to Stop Network Activity From Waking Your PC on Windows 7, 8 and 8.1
To edit this particular setting, you need to open the Windows Device Manager. The easiest way is to search from for “device manager” and press enter. This generic method of opening the Device Manager should work with most versions of Windows.
Expand network adapters and right-click on the one you want to change the setting for, then choose 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.