Uhm, this happens to me when I'm at my dad's (MAC).
[17:47:15 INFO]: Looking for orphaned versions to clean up...
[17:47:15 INFO]: Looking for old natives & assets to clean up...
[17:47:16 INFO]: Client> Exception in thread "main" java.lang.UnsatisfiedLinkError: /Users/ashleybailey-whitt/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1399762035244389000/liblwjgl.jnilib: Library not loaded: @rpath/libjawt.dylib Referenced from: /Users/ashleybailey-whitt/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1399762035244389000/liblwjgl.jnilib Reason: image not found
[17:47:16 INFO]: Client> at java.lang.ClassLoader$NativeLibrary.load(Native Method)
[17:47:16 INFO]: Client> at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1861)
[17:47:16 INFO]: Client> at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1778)
[17:47:16 INFO]: Client> at java.lang.Runtime.loadLibrary0(Runtime.java:823)
[17:47:16 INFO]: Client> at java.lang.System.loadLibrary(System.java:1045)
[17:47:16 INFO]: Client> at org.lwjgl.Sys$1.run(Sys.java:73)
[17:47:16 INFO]: Client> at java.security.AccessController.doPrivileged(Native Method)
[17:47:16 INFO]: Client> at org.lwjgl.Sys.doLoadLibrary(Sys.java:66)
[17:47:16 INFO]: Client> at org.lwjgl.Sys.loadLibrary(Sys.java:95)
[17:47:16 INFO]: Client> at org.lwjgl.Sys.<clinit>(Sys.java:112)
[17:47:16 INFO]: Client> at azi.K(SourceFile:2153)
[17:47:16 INFO]: Client> at net.minecraft.client.main.Main.main(SourceFile:76)
[17:47:18 ERROR]: Game ended with bad state (exit code 1)
[17:47:18 INFO]: Ignoring visibility rule and showing launcher due to a game crash
[17:47:18 INFO]: Deleting /Users/ashleybailey-whitt/Library/Application Support/minecraft/versions/1.7.4/1.7.4-natives-1399762035244389000