PC is turning on intermittently

After I tu off my computer (or hibeate specifically) It tu on sometime later. It seem not to happen regularly. (Or I think so).

I tried to disable all scheduled tasks with "Autoruns" program, but it doesn't seem to help.

And another thing - I had this problem on my older computer and then I basically "bought" new one, new windows etc. and it started again. (Windows 10 on both, but not sure. might be earlier version also)

Can you help me troubleshoot it?

Thank you.