Games : Game Output Error Message

I really have no idea what I'm doing here, I don't know a thing about Minecraft other than my daughter can no longer play it on our PC. I've uninstalled and reinstalled MULTIPLE times, installed and then uninstalled Java, and no matter what I've tried, when we click Play, it ALWAYS goes to the Game Output tab with the same message: [12:08:40] [Client thread/INFO]: Setting user: TEM0606 [12:08:40] [Client thread/INFO]: (Session ID is token:1e0eb726f5a940089489b7a8beedca67:3084b0cd4c6342e8b457cd1507f79512) 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 lu.b(SourceFile:151) at lu.(SourceFile:43) at net.minecraft.server.MinecraftServer.(SourceFile:155) at bpp.(SourceFile:41) at avf.(SourceFile:293) 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

I am SOOOOOOO clueless what ANY of this means, and I am so computer un-savvy, that no forum question seems to fit what I am having trouble with. I've tried sending messages to Mojang, which only direct me the articles about troubleshooting, I've tried tweeting "experts," and I can't get ANYWHERE. If anyone can "dumb this down" for me so she can play again someday, I would REALLY appreciate it!!!