Screen randomly freezing on Windows 10 PC

Any idea how to diagnose this,I have no idea from where to even begin

I have a laptop connected to a monitor which(the laptop supports 240hz(2560x1600)and the monitor 60hz...and up to 1920x1080p)
The project mode is set to make only the monitor active(second screen only)
Randomly for some reason,everything just kinda freezes.
For example nothing is updated on the screen(except the mouse,for some reason there is no problem with it at all,all mouse movements are displayed correctly),when I try to minimize a window,this happens after maybe 5 seconds,when I press the windows key,the start menu appears after around 5 seconds
Ctrl+Alt+Delete the screen appears after 5 seconds
It's not high gpu/cpu load,I will hears the fans if it was that and I have

When I switch the projector(Windows key+P)to the laptop screen only and everything start working and when I switch to the monitor only again,the problem is fixed for I don't know how long