Probleme de lancement

Voila ,
enfait après une réinstallation complète de windows 7 quand je lance le launcher de minecraft il me dit ça :

"Bootstrap (v5)
Current time is Dec 25, 2013 1:25:27 PM
System.getProperty('os.name') == 'Windows 7'
System.getProperty('os.version') == '6.1'
System.getProperty('os.arch') == 'x86'
System.getProperty('java.version') == '1.7.0_25'
System.getProperty('java.vendor') == 'Oracle Corporation'
System.getProperty('sun.arch.data.model') == '32'

Looking for update
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma
Got reply in: 2552ms
Didn't find an update in time.
Reversing LZMA on C:\Users\Quentin!\AppData\Roaming\.minecraft\launcher.pack.lzma to C:\Users\Quentin!\AppData\Roaming\.minecraft\launcher.pack
Unpacking C:\Users\Quentin!\AppData\Roaming\.minecraft\launcher.pack to C:\Users\Quentin!\AppData\Roaming\.minecraft\launcher.jar
No update found.
Cleaning up C:\Users\Quentin!\AppData\Roaming\.minecraft\launcher.pack
Starting launcher.
FATAL ERROR: java.lang.ExceptionInInitializerError
at org.apache.logging.log4j.util.PropertiesUtil.<init>(PropertiesUtil.java:71)
at org.apache.logging.log4j.util.PropertiesUtil.<clinit>(PropertiesUtil.java:31)
at org.apache.logging.log4j.status.StatusLogger.<clinit>(StatusLogger.java:48)
at org.apache.logging.log4j.LogManager.<clinit>(LogManager.java:44)
at net.minecraft.launcher.Launcher.<clinit>(Launcher.java:58)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at net.minecraft.bootstrap.Bootstrap.startLauncher(Bootstrap.java:240)
at net.minecraft.bootstrap.Bootstrap.execute(Bootstrap.java:124)
at net.minecraft.bootstrap.Bootstrap.main(Bootstrap.java:381)
Caused by: java.lang.NullPointerException
at org.apache.logging.log4j.util.ProviderUtil.<clinit>(ProviderUtil.java:70)
... 12 more


Please fix the error and restart."

Alors si quelqu'un pourrais m'aider a résoudre ce problème , merci a lui.