I encountered quite a few times with such problem.
I would try to:
1. turn off from bios "USB wake up from S3" and "Power on by keyboard" and "Wake on LAN". Would suggest go though the bios and disable everything that is associated with "sleep" and "wake up"
2. Try updating graphics driver or reverting to manufacturers original drivers.
As i understand that fresh windows install did not have that kind of problem.
I would verifiy the version of graphics driver and if update/original driver did not help, then copy from frest windows install GPU drivers to the problematic windows (use program called "double driver")
3. Doubt this will work, but try disabling "Fast boot" from "power options" menu.
4. Try disabling as picture shown below:
5. Type into command prompt: "powercfg –lastwake" and look what woke up the computer and do the conclusions
Before doing any software work i would suggest to clone to another disk incase something goes terribly wrong and windows wont boot, so you can recover and try another method.