Probleme carte graphique Windows7

Bonjour,
Je voulais joué a minecraft mais depuis que jai mis a niveau windows mais jai eu un message d'erreur
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 23/02/12 18:54

Minecraft: Minecraft 1.1
OS: Windows 7 (x86) version 6.1
Java: 1.6.0_30, Sun Microsystems Inc.
VM: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
LWJGL: 2.4.2
[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:230)
at net.minecraft.client.Minecraft.run(SourceFile:648)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT ef5954cc ----------
Je croit que ma carte graphique et instalé c'est un ATI HD Radeon 2300 Sur un pc Acer 7720G (C'est un pc portable)