почему не работает minecraf?помогите плиз

Bad video card drivers!
-----------------------

Minecraft was unable to start because it failed to find an accelerated OpenGL mode.
This can usually be fixed by updating the video card drivers.

--- BEGIN ERROR REPORT 7fe0271 --------
Generated 13.11.12 16:50

- Minecraft Version: 1.4.2
- Operating System: Windows 7 (x86) version 6.1
- Java Version: 1.7.0_07, Oracle Corporation
- Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
- Memory: 465405728 bytes (443 MB) / 518979584 bytes (494 MB) up to 1037959168 bytes (989 MB)
- JVM Flags: 2 total; -Xms512m -Xmx1024m
- AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
- LWJGL: 2.4.2
- OpenGL: ~ERROR~ NullPointerException: null
- Is Modded: Probably not
- Type: Client
- Texture Pack: ~ERROR~ NullPointerException: null
- Profiler Position: N/A (disabled)
- Vec3 Pool Size: ~ERROR~ NullPointerException: null[failed to get system properties (java.lang.NullPointerException)]

org.lwjgl.LWJGLException: Pixel format not accelerated
at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)
at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)
at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:185)
at org.lwjgl.opengl.Display.createWindow(Display.java:311)
at org.lwjgl.opengl.Display.create(Display.java:856)
at org.lwjgl.opengl.Display.create(Display.java:784)
at org.lwjgl.opengl.Display.create(Display.java:765)
at net.minecraft.client.Minecraft.a(SourceFile:232)
at net.minecraft.client.Minecraft.run(SourceFile:515)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT bc843b78 ----------

что значит это????