Why does the computer not start up and keep restarting?

A computer that won't start up and keeps restarting may be experiencing hardware issues, such as faulty RAM, a failing power supply, or overheating components. Software problems, like corrupt system files or a problematic update, can also cause boot loops. Additionally, loose connections or peripheral devices may interfere with the startup process. Troubleshooting steps include checking hardware connections, booting in safe mode, or performing a system restore.