Unreal Engine 4 Crash

Hello everyone, I’ve just downloaded epic games lucher and installed the UE4 in my pc. The problem is that after open it and my working file the pc crashes with a sign with " activating " written on it and suddenly my keyboard stop working, then my mouse and in the end all programs crashes.

I’m using w7 ultimate, intel core i5 4690 with 3.5ghz, 8gb ram, and a amd saphire readon r7 260x

Sorry for my english but it’s not my native language.
Hope u all can help me !
( I can’t upload a screen of the error 'cause pc crashes and can’t take a print, if u need it i will do with my phone later )

Cya !

Pretty strange. Please take a picture with your phone and post it.