Hello i have a problem, i cannot launch the game game since yesterday. when i try to open the game about the launcher, following opening and the game doesnt run:

[13:29:27] [Client thread/INFO]: Setting user: chillahkalle18
[13:29:28] [Client thread/INFO]: (Session ID is token:5a470edb1c2848f68b712234b6477c65:ee78da2dbe6943a3a2d3d07488d086e1)
Exception in thread "Client thread" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
at com.google.gson.Gson.fromJson(Gson.java:815)
at com.google.gson.Gson.fromJson(Gson.java:768)
at sa.b(SourceFile:148)
at sa.<init>(SourceFile:42)
at net.minecraft.server.MinecraftServer.<init>(SourceFile:154)
at cyk.<init>(SourceFile:40)
at bss.<init>(SourceFile:285)
at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
at com.google.gson.Gson.fromJson(Gson.java:803)
... 7 more
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

by clicking on Launcher log their stands:

[13:35:00 INFO]: Launching game
[13:35:00 INFO]: Unpacking natives to C:\Users\Pascal\AppData\Roaming\.minecraft\versions\1.8.3\1.8.3-natives-47829878205816
[13:35:00 INFO]: Launching in C:\Users\Pascal\AppData\Roaming\.minecraft
[13:35:00 INFO]: Half command: C:\Program Files (x86)\Minecraft\runtime\jre-x64\1.8.0_25\bin\javaw.exe -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M -Djava.library.path=C:\Users\Pascal\AppData\Roaming\.minecraft\versions\1.8.3\1.8.3-natives-47829878205816 -cp C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\oshi-project\oshi-core\1.1\oshi-core-1.1.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\net\java\dev\jna\jna\3.4.0\jna-3.4.0.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\net\java\dev\jna\platform\3.4.0\platform-3.4.0.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\ibm\icu\icu4j-core-mojang\51.2\icu4j-core-mojang-51.2.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\io\netty\netty-all\4.0.23.Final\netty-all-4.0.23.Final.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\google\guava\guava\17.0\guava-17.0.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\commons-codec\commons-codec\1.9\commons-codec-1.9.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\google\code\gson\gson\2.2.4\gson-2.2.4.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\mojang\authlib\1.5.17\authlib-1.5.17.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\com\mojang\realms\1.7.9\realms-1.7.9.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\commons\commons-compress\1.8.1\commons-compress-1.8.1.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\httpcomponents\httpclient\4.3.3\httpclient-4.3.3.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\commons-logging\commons-logging\1.1.3\commons-logging-1.1.3.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\httpcomponents\httpcore\4.3.2\httpcore-4.3.2.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\logging\log4j\log4j-api\2.0-beta9\log4j-api-2.0-beta9.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\apache\logging\log4j\log4j-core\2.0-beta9\log4j-core-2.0-beta9.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.4-nightly-20150209\lwjgl-2.9.4-nightly-20150209.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.4-nightly-20150209\lwjgl_util-2.9.4-nightly-20150209.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\libraries\tv\twitch\twitch\6.5\twitch-6.5.jar;C:\Users\Pascal\AppData\Roaming\.minecraft\versions\1.8.3\1.8.3.jar net.minecraft.client.main.Main
[13:35:01 INFO]: Looking for orphaned versions to clean up...
[13:35:01 FATAL]: Fatal error launching game. Report this to http://bugs.mojang.com please!
java.io.FileNotFoundException: File 'C:\Users\Pascal\AppData\Roaming\.minecraft\assets\indexes\legacy.json' does not exist
at org.apache.commons.io.FileUtils.openInputStream(FileUtils.java:299) ~[launcher.jar:1.6.11]
at org.apache.commons.io.FileUtils.readFileToString(FileUtils.java:1711) ~[launcher.jar:1.6.11]
at net.minecraft.launcher.Launcher.cleanupOrphanedAssets(Launcher.java:253) ~[launcher.jar:1.6.11]
at net.minecraft.launcher.Launcher.performCleanups(Launcher.java:495) ~[launcher.jar:1.6.11]
at net.minecraft.launcher.game.MinecraftGameRunner.launchGame(MinecraftGameRunner.java:221) ~[launcher.jar:1.6.11]
at com.mojang.launcher.game.runner.AbstractGameRunner.onDownloadJobFinished(AbstractGameRunner.java:186) [launcher.jar:1.6.11]
at com.mojang.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:122) [launcher.jar:1.6.11]
at com.mojang.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:12) [launcher.jar:1.6.11]
at com.mojang.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:86) [launcher.jar:1.6.11]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_25]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_25]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_25]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_25]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
[13:35:03 ERROR]: Game ended with bad state (exit code 1)
[13:35:03 INFO]: Ignoring visibility rule and showing launcher due to a game crash
[13:35:03 INFO]: Deleting C:\Users\Pascal\AppData\Roaming\.minecraft\versions\1.8.3\1.8.3-natives-47829878205816
[13:35:03 WARN]: Couldn't delete C:\Users\Pascal\AppData\Roaming\.minecraft\versions\1.8.3\1.8.3-natives-47829878205816 - scheduling for deletion upon exit

Now my question is

what is the problem and how can i resolve it?
is my Graphicdriver outdated or something else?

before yesterday the game runs without problems.....