Minecraft crashes at start?

The moment i open the game it crashes and i get a text document with that error message and my pc is fully up to date specs:

AMD A8-6600K 3.9GHz cpu
Amd Radeon R7 200 Series
6gb ram
Windows 7 Pro 64 Bit

I upgraded to windows 10 but then downgraded back to windows 7 now it don't work.

Error message:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ILLEGAL_INSTRUCTION (0xc000001d) at pc=0x000007fef87fca90, pid=3336, tid=5420
#
# JRE version: Java(TM) SE Runtime Environment (8.0_66-b17) (build 1.8.0_66-b17)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.66-b17 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C [msvcr120.dll+0x8ca90]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows

Cbxvv