Hi GauntherODimm.

Is/are your CPU or/and GPU over-clocked in any way (power limit/clocks)? If so, revert to the default settings and disable over-clocking on every piece of hardware.
Also make sure you have installed the redistributables found in the game's folder appropriately.
Please describe how and when the crash occurs and any reason you might have in mind as to why.

Cheers.

Hello Fate is on edge,

The game crashes randomly when I play the Witcher 3 on 1440 resolution at ''ultra'' settings. Sometimes it doesn't and sometimes it does.

Can it be because of my CPU?
http://i66.tinypic.com/29n9zlg.jpg

Hi again GauntherODimm.

If your CPU was utilized on 100%, for the duration of your session, then this would cause it to overheat. In that case, if your motherboard includes temperature protection measures, it would most probably shut down your PC before giving you a beeping notice.
Another case that I can think of is, whether you are running a lot of background applications or a Windows 10 OS update causing performance instability or a virus infecting your PC, you should boot the OS in "safe mode without Internet".
https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode
Is this the only application you observe weird behavior with?
P.S.; You could try to fiddle with the "PhysX " settings of your GPU drivers, so that physics are calculated by the CPU instead or the opposite, and see if that stabilizes the game. Also I would recomend turning off any physics in the game's settings and namely, "Hairworks".

Cheers.