Hi marmalade_skies
I am Dave, an Independent Advisor, I will help you with this . . .
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 of Windows will boot to the login screen . . .
Go to Troubleshoot - Advanced Option - Startup Repair
See if Windows startup can repair itself
Go to Troubleshoot - Advanced Option - System Restore
Check to see if you have a restore point you can go back to