How to shutdown a computer if inactive for certain minutes?

Hi Guys,

We have a supercomputer which is accessed by all of our production. This PC has configured to turn ON automatically at 8.00 AM every day using the BIOS feature. As per our instruction the last user who accesses the PC supposed to shut down the computer.

But our problem no one able to confirm who is accessing the computer in the last. This makes the PC left ON all night time. I cannot plan shutdown using task scheduler because If I force shutdown the PC any user is working on will make a problem to us.

So, How to shut down a computer if inactive for certain minutes? How to confirm if the PC is inactive?

Thanks