Close all processes using Python | Python Automation

when all of the applications get closed, the system processes also get closed right. Would it not cause any system instabilities?

How to get that wallpaper

After closing all the applications, I want to Restart my PC by using script. And after restarting the PC, specific Applications have to open. Can you help me in this?

i have virus called Tiworker.exe, i use above code but received error:The process with PID 4420 could not be terminated.
Reason: Access is denied.