Startup error - Can't load IA 32-bit .dll on a AMD 64-bit platform

Does it still happen in launcher version 1.1.2?

How do I get that?

When you restart the launcher, it automagically updates.

Still not working

Launching game
Looking for old natives to clean up...
Unpacking natives to C:\Users\Danny\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2-natives-7296323276875
Launching in C:\Users\Danny\AppData\Roaming\.minecraft
Running C:\Program Files\Java\jre7\bin\javaw.exe -Xmx1G -Djava.library.path=C:\Users\Danny\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2-natives-7296323276875 -cp C:\Users\Danny\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar;C:\Users\Danny\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar;C:\Users\Danny\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2.jar net.minecraft.client.main.Main --username Kent_Shadows --session token:1817ed814f9f4f0b93802a14f35b86ea:74e463869f3c4ba286559358706443f3 --version 1.6.2 --gameDir C:\Users\Danny\AppData\Roaming\.minecraft --assetsDir C:\Users\Danny\AppData\Roaming\.minecraft\assets
Client> Exception in thread "main" java.lang.UnsatisfiedLinkError: C:\Users\Danny\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2-natives-7296323276875\lwjgl.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform
Client> 	at java.lang.ClassLoader$NativeLibrary.load(Native Method)
Client> 	at java.lang.ClassLoader.loadLibrary1(Unknown Source)
Client> 	at java.lang.ClassLoader.loadLibrary0(Unknown Source)
Client> 	at java.lang.ClassLoader.loadLibrary(Unknown Source)
Client> 	at java.lang.Runtime.loadLibrary0(Unknown Source)
Client> 	at java.lang.System.loadLibrary(Unknown Source)
Client> 	at org.lwjgl.Sys$1.run(Sys.java:73)
Client> 	at java.security.AccessController.doPrivileged(Native Method)
Client> 	at org.lwjgl.Sys.doLoadLibrary(Sys.java:66)
Client> 	at org.lwjgl.Sys.loadLibrary(Sys.java:95)
Client> 	at org.lwjgl.Sys.<clinit>(Sys.java:112)
Client> 	at ats.F(SourceFile:1869)
Client> 	at net.minecraft.client.main.Main.main(SourceFile:37)
Game ended with bad state (exit code 1)
Ignoring visibility rule and showing launcher due to a game crash
Deleting C:\Users\Danny\AppData\Roaming\.minecraft\versions\1.6.2\1.6.2-natives-7296323276875

Please uninstall everything on your computer what sounds like Java. Every version.
Then install only Java 1.7 U25 for 64 bit systems. Nothing else.

Still got the same error...

I'm out of ideas.
Please use the Mojang Support Center, especially the help chat: http://webchat.esper.net/?channels=minecrafthelp or irc://irc.esper.net/minecrafthelp , there are good problem solvers over there.
If you go there, please refer to this ticket.

lwjgl.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform

It appears to have downloaded the wrong natives. Do you have an AMD or Intel system?

It doesn't matter if one has an Intel x86-64 or AMD x86-64 CPU, for Java those are treated as AMD 64:
Mine is an Intel Core 2 Quad, but reported as:

Operating System: Windows 7 (amd64) version 6.1

Cannot imagine that there is a IA-32 version of Java 7 ? (IA = Itanium Architechture)
(Forget the last sentence)

Found some useless fun facts in http://lwjgl.org/forum/index.php?topic=3585.msg23301#msg23301 but not an answer to the original issue:

It is called AMD 64 simply because AMD's lawyers won the race to the trademark/patent office. Intel licensed AMD's 64 bit architecture for their own use because the design was much more efficient and ran at lower power. Oddly enough, Intel wound up managing said power usage and heat management better in the finished product, as anyone who has had an AMD x2 64 laptop heatsink burn their leg would tell you, lol!

Some more strange hints:
http://www.minecraftforum.net/topic/829299-black-screen-of-death-problem/

Switch off Avira Antivirus

http://forums.technicpack.net/threads/lwjgl-fails-to-load.19653/

The LWJGL website has a tutorial on how to test if LWJGL is working properly. If you try out that test app with a few debug switches, then you can find a lot of useful data. My issue was an inpage error. They come from various sources, but most commonly from storage or RAM faults. After running a checkdisk scan on the disk, it turns out there was a few faulty sectors and the checkdisk actually made it worse. I found a spare disk and everything is working fine now, but I am going to need a new SSD.

Did you ever try to reinstall Minecraft ?

I have done that, but I've noticed I don't have a saves file. Might that be an issue?

I've also tried 1.5.2, since I know that worked on my laptop, but that just tries to load but closes automatically, saying:

Game ended with no troubles detected (exit code 0)

Does that help?

I'm afraid not.
The "saves" folder will be created at the first successful start of the game.

It's trying to load the 32 bit lwjgl.dll in 64 bit Java. That doesn't work. Either lwjgl64.dll is missing from the appropriate folder, or there's a configuration problem.

I've had a root around in the .minecraft folders, and without going into the jar files, I can't find either. Could you tell me where it should be?