I am currently writing from a computer on which a VM has just frozen due to exhausted RAM. I am obviously no expert in the field of operating systems but i know that they implement certain memory management methods so why can't my OS handle my alt-f4 request to kill the troublesome process in a reasonable time?

Why can't other processess still run normally?

Shouldn't operating system swap between active tasks so that my keyboard input reaches said process?

Operating system in itself should be of top priority with handling user input isn't that right?

Therefore my question remains: how come, despite all the round-robin and/or other scheduling mechanics my OS still freezes?

Thank You for all the answers. Cheers.