Why Does minecraft Keep Crashing and not letting me play?

Why does minecraft keep crashing? I recently bought the prepaid card for 26.95 and i used the code. Everything works but when i try to launch it up it just says this. It won't start up. It just keeps saying this. I really want to play. Can anyone help? Do i need to install something?

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

Time: 1/20/14 4:21 PM
Description: Initializing game

java.lang.NullPointerException: Initializing game
at azi.a(SourceFile:495)
at azi.ad(SourceFile:300)
at azi.f(SourceFile:696)
at net.minecraft.client.main.Main.main(Sour…

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

-- Head --
Stacktrace:
at azi.a(SourceFile:495)
at azi.ad(SourceFile:300)

-- Initialization --
Details:
Stacktrace:
at azi.f(SourceFile:696)
at net.minecraft.client.main.Main.main(Sour…

-- System Details --
Details:
Minecraft Version: 1.7.4
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 4816632 bytes (4 MB) / 26808320 bytes (25 MB) up to 518979584 bytes (494 MB)
JVM Flags: 2 total; -XX: HeapDumpPath=MojangTricksIntelDriver… -Xmx512M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.7.4
LWJGL: 2.9.1
OpenGL: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
GL Caps:
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)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null
Anisotropic Filtering: Off (1)

Go to run, type %appdata%.

You can see the.minecraft Folder.

Delete it, and launch Minecraft. It should work.

Hope, this helped. If not, please contact me for more help.