There are Different problems for windows not Booting ..
Some Of Them Are .
1. File Missing.
2. Hardware Changes
3. Spyware applications
4. Graphics Card Drivers
Try Booting The Windows In Safe Mode
Safe Mode Screen
When Your PC Won’t Boot In To Windows, All You Need to Do Is Boot The Windows in Safe Mode.
Use The F8 Key To Do This. After Restarting Your System You Need Press The F8 Key On Your Keyboard When The System Starts up To Access The Safe Mode Menu. If Your Windows Is Able To Boot In Safe Mode You Need To Remove Unwanted Programs , Scan Your System With Antivirus Programs, Check For Missing Drivers Files.