This is a problem with dozens of potential solutions, but in my experience 75% of the time it is the network card that is walking up a Windows PC and the solution is fast and simple.
- Bring up a CMD prompt
- Type POWERCFG -LASTWAKE
To disable the network cards ability to wake up your PC:
- Bring up DEVICE MANAGER (in Windows 8’s TILES screen just type the word DEVICE MAN)
- Find your network card and either:
- UNcheck ALLOW THIS DEVICE TO WAKE THE COMPUTER, or
- CHECK, ONLY ALLOW A MAGIC PACKET TO WAKE THE COMPUTER
If you still have issues there are several other processes you should follow:
- Update device drivers, and I don’t mean from Windows Update. Go to the manufacturers website and download / install the most current drivers. Go to intel.com/support/detect.htm and run the CHECK YOUR SYSTEM FOR LATEST DRIVERS.
- In Windows bring up your POWER OPTIONS and check that they are as you expect. When in doubt click the RESTORE DEFAULT SETTINGS FOR THIS PLAN
- Play with the settings in the command line POWERCFG. Bring up a CMD prompt and type POWERCFG /? to see all the options
- Run a Windows Update and patch everything