when i shut down my computer and open it again my system will restart and restart...

If your computer restarting abruptly, then there must be some problem in the system such as overheating of hard disk, due to faulty RAM or hard disk, external use of USB to system or some software crashes on operating system. Check these problems with the technicians.

A real problem is with your PC, shut down unexpectedly. Why does this happen for many reasons, but also how to deal with different ways. The sudden closure of a PC problem is that it will not only damage your computer's power, but it can damage the operating system and damage files and data. It is better to repair the computer again before the first question.