Try starting it up in "Safe Mode" and see if it will load. If it does, then you know it is software and not hardware. So then check anything you recently downloaded, installed, etc. You may even want to go to "System Restore" and select a restore point prior to the time the problem started.
If, however, you can't get in even in "Safe Mode" then it may well be either a full OS restore needed or a hardware issue.
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 "F4" key to Enable "Safe Mode".
(The computer will then start in "Safe Mode" with a minimal set of drivers and services.)
b. Press the "F5" key to Enable...