minecraft is not opening

Put the summary of the bug you're having here

What I expected to happen was...:
I don't know what happened.

What actually happened was
I clicked Play Demo on the launcher and after some seconds there was a crash repot infront of me...

CRASH REPORT

Minecraft Crash Report ----
// You're mean.

Time: 5/30/16 10:54 PM
Description: Initializing game

java.lang.NullPointerException: Initializing game
at bcd.a(SourceFile:750)
at bcd.ar(SourceFile:627)
at bcd.an(SourceFile:435)
at bcd.a(SourceFile:384)
at net.minecraft.client.main.Main.main(SourceFile:124)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Thread: Client thread
Stacktrace:
at bcd.a(SourceFile:750)
at bcd.ar(SourceFile:627)
at bcd.an(SourceFile:435)

– Initialization –
Details:
Stacktrace:
at bcd.a(SourceFile:384)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.9.4
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 85306104 bytes (81 MB) / 149299200 bytes (142 MB) up to 523501568 bytes (499 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.9.4
LWJGL: 2.9.4
OpenGL: ~_ERROR~ RuntimeException: No OpenGL context found in the current thread.
GL Caps:
Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: ~_ERROR~ NullPointerException: null
Profiler Position: N/A (disabled)
CPU: bcd$7@f70249

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...