while playing lfs if i turn quickly the game goes to desktop. I'm 110% sure
It's the mouse It's enough to move it and press some buttons on it and you're watching the desktop of ur pc. Happens with different mouses connected.

cheers.

Are you running LFS in full-screen or windowed mode? If you're running in windowed mode you could be moving the mouse outside the LFS window, where clicking would make LFS lose focus.

I'm running the game full screen

Check to make sure you're not running multiple monitors (unless you legitimately are), even if you're running LFS full screen, and you click somewhere other than LFS, it'll escape to your desktop. Try ctrl+c to clip the mouse to window.