I clicked on the 'Play' Button at the bottom of the 1.6.2 launcher & this happened:
java.lang.NoClassDefFoundError: org/apache/commons/io/filefilter/AgeFileFilter
at net.minecraft.launcher.GameLauncher.cleanOldNatives(GameLauncher.java:342)
Launcher 1.1.2 (through bootstrap 4) started on windows...
Current time is Jul 23, 2013 4:40:50 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'
Loaded 1 profile(s); selected 'TheSebdroid'
Refreshing auth...
Logging in with access token
Getting syncinfo for selected version
Queueing library & version downloads
Download job 'Version & Libraries' started (8 threads, 19 files)
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\net\java\jinput\jinput-platform\2.0.5\jinput-platform-2.0.5-natives-windows.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl-platform\2.9.0\lwjgl-platform-2.9.0-natives-windows.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar for job 'Version & Libraries': Used own copy as it matched etag
Finished downloading C:\Users\Sebastian Jose\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2.jar for job 'Version & Libraries': Used own copy as it matched etag
Job 'Version & Libraries' finished successfully
Delta time to compare resources: 113000 ms
Download job 'Resources' skipped as there are no files to download
Job 'Resources' finished successfully
Launching game
Looking for old natives to clean up...
Fatal error launching game. Report this to http://mojang.atlassian.net please!
java.lang.NoClassDefFoundError: org/apache/commons/io/filefilter/AgeFileFilter
at net.minecraft.launcher.GameLauncher.cleanOldNatives(GameLauncher.java:323)
at net.minecraft.launcher.GameLauncher.launchGame(GameLauncher.java:175)
at net.minecraft.launcher.GameLauncher.onDownloadJobFinished(GameLauncher.java:493)
at net.minecraft.launcher.updater.download.DownloadJob.startDownloading(DownloadJob.java:75)
at net.minecraft.launcher.Launcher$1.run(Launcher.java:157)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.io.filefilter.AgeFileFilter
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 11 more
Reinstall Java: Uninstall everying looking like Java from your computer. Install Java 1.7 U25 from here: http://www.java.com/en/download/
Reinstall Minecraft :http://hopper.minecraft.net/help/reinstalling-minecraft