Last time you turned on your computer, Windows started correctly. Now Windows starts but fails before the login prompt. What is the first step you should try to troubleshoot this problem?

Restoring a system image is a drastic measure for severe system corruption and should be considered only after simpler troubleshooting steps, such as a normal restart, have failed.

Last Known Good Configuration is a valid troubleshooting step for boot issues but is typically attempted if a normal restart does not resolve the problem, especially if a recent change is suspected.

Safe Mode with Command Prompt is a more advanced diagnostic mode for complex issues and typically used after simpler Safe Mode options or normal restarts have failed.

If Windows fails to load completely but started correctly last time, the problem could be a temporary glitch. The first, simplest, and least intrusive troubleshooting step is always to try restarting the computer and selecting 'Start Windows Normally' to see if the problem resolves itself without further intervention.