Can you boot into Safe Mode from the Recovery Environment using these steps?
Start your PC, just as Windows attempts to load (spinning dots), press and hold Power Button for 5 - 10 seconds to perform a Hard Shut Down.
Do this twice
On the third start Windows will boot into the Recovery Environment and from there you can access System Repair, Safe Mode, Command Prompt... etc.
Please try each option one at a time, then see if Windows will boot.
Go to Troubleshoot - Advanced Option - Startup Settings and click Restart
Upon restart, press 5 to enter Safe Mode