PC Won't Boot – Windows Won't Start

If Windows won't start, the cause is often a corrupted boot process, a faulty update, or a loose cable. Hard-restart the PC two or three times (hold the power button until it shuts off) to trigger Windows Automatic Startup Repair – Windows will detect the problem and attempt to fix it on its own. If a menu appears, select 'Troubleshoot' > 'Advanced Options' > 'Startup Repair'. If that doesn't help, try 'System Restore' under the same options to roll Windows back to an earlier, working state. First check whether a USB drive or external hard drive is connected – these can interfere with the boot process and should be removed. If nothing works, a Windows installation media (created for free from microsoft.com) can be used for repair; if in doubt, consult a professional.