Verify your game files if you are using Steam… You may have to do this more than once to be sure.
Temporarily change your in-game graphics to 1080p, 60fps foreground framerate limited, all graphics to very low or disabled… If this gets you past the crash point, then you can increase the resolution (only), then the fps (but keep it limited to your monitor or less) and lastly if everything is still stable, then increase the in-game graphics one step at a time testing between each change. It is not recommended that you go above Medium settings if you are finding the game unstable.
Make sure that your operating system is fully patched and that ALL drivers are up to date - not just the graphics driver.
Dont run any overlay applications (Steam, Nvidia etc) and disable or dont run any other apps while you are playing LE.