Can't start

I installed v4.14 succefully, then i pressed ‘start’ button, but nothing happened !
not any interface, not any error information , nothing.
even the same as v4.13.2
could anyone help me?
my computer configuration:
i7 6700k+gtx1070
os win8.1

Hello,

I’m sorry that you are having an issue with the Epic Games Launcher. In order for us to offer the best support, we have recently modified the process for how Epic Games can help troubleshoot your Launcher issue. Please visit http://help.epicgames.com/ for technical support, here you can find information and solutions for common issues, as well as a contact form if you still need additional assistance. To access the contact form, please use the “Email Us” button under the “Contact Us” section. Thanks!

Have a great day