So I'm not sure if anyone else has this problem, but when I got WINDOWS 8 every time I put my computer to sleep it turns itself back on. Now I will say this YES I do have a mouse. AND YES it is turned off. Yes the computer lid has stoppers on the bezel of my laptop screen that keep it from hitting the keys. the power button is in a strategic place where it can't be pressed by the screen.
The next time this happens open cmd and type "powercfg -lastwake" This will let us see what is causing it to wake up.
I know this doesn't answer your question directly, but why do you still have Windows 8? The upgrade to 8.1 is free in the Microsoft Store.
This is was what the cmd said. Wake History count -1
wake history{0}
Search "Power and Sleep Settings" and see what it says. I have mine set to never go to sleep or anything unless I press the power button. I also don't use the software sleep button, only the physical button to sleep. Whenever I have my mouse plugged in nothing happens. I hope this helps in some way, pal.
That was the first one I tried.
have you checked the task scheduler if there is some task that wakes it from sleep?
How would it wake it up from sleep? You mean the task manager right?