Let it drain fully (the battery) and remove the charger cord. So that it is completely powerless and will turn off. Then plug it in and try turning it on. If it doesn't, or goes right into hibernation again, then I would try unplugging the power again, let it turn off fully, again, and when you go to restart it, do so in "Safe Mode". This should get you around the issue and let you get into windows to check the sleep settings.
That said, if even that won't work, then there may be something on the computer (malicious software) or a hardware issue preventing this.
How to enter "Safe Mode" when booting the computer.
In Windows 8 and 10 ...
As your computer restarts, press F8 (possibly a few times) to enter "Safe Mode"
a. Press the...