How to see what processes are running in idle mode?

Question

Windows

Hello everyone, I have a laptop with windows 7 x64. The problem is that as soon as the screen saver ( blank page ) starts, the load on the processor and hard disk grows. The cooling fan starts spinning at full speed.
As I understand it, some processes are launched that do something.
How to see which ones and what they do?

Answer 1

Windows service starts. Defragmentation for example or archiving.

Answer 2

Process explorer (in performance graph mode will show at least sources of spikes)
FileMon will show file accesses.
PSTools from there also allows you to remotely watch processes, however, from the command line.