Windows 10 user interface stops responding - what to do?

My Windows 10 notebook is no longer responsive to clicks / inputs with my BT mouse or not even with the mouse pad. Start menu, icons, taskbar - nothing stops responding, what can I do? I have an HP Pavilion 15-bc300ng that is only about 5-6 months old.

Win10 (64bit system)
128GB SSD
1TB HDD
Nvidia GeForce GTX 950m
Processor: i5 7200u

Keystrokes are still recognized.

Always first shut down and then reboot.

Okay, I'll do that, then get in touch again

Worked. But why is that? Start menu often can't be clicked.

Windows 10 is just not a super system