Why can't I stop running?

Solution 1:

Check your keystroke repeat rate/repeat delay and turn it down if you have to. I used to run into the same thing back in the day when playing Unreal Tournament and it turned out that the keystroke repeat was kicking in and that was what was keeping me running in the same direction even though I would have different keys held down.

XP & Win7 both: Start > Control Panel > Keyboard

Solution 2:

You need to update LWJGL. From the Minecraft Wiki:

http://lwjgl.org/download.php

Select the latest stable release and download the lwjgl-X.X.X.zip. You should also backup your .minecraft folder before following the steps below. As a last resort, you can use the Minecraft Launcher's Force Update option to reset the files.

• With 2.8.1, on most 64 bit computers, the lwjgl64.dll update will cause a black screen crash. You can revert to the backup version you have saved if needed.
• Again on several 64 bit computers, the OpenAL64.dll update can cause a sound glitch that makes bursting sounds. Keep a backup in case you need to rollback.
• Version 2.8.5 generally breaks shift-clicking; 2.8.4 and 2.9.0 do not. You can change the url in your browser to access 2.8.4 or 2.9.0 rather than 2.8.5.
• LWJGL 2.8.5 has a bug which sends a false signal that the user released all currently pressed keyboard keys when a mouse button is pressed. That means that your building will be significantly slower. Do not update to this version if this bothers you.

This bug seems to be fixed when playing in fullscreen mode (Default F11), or updating to LWJGL 2.9.0.

Note that versions of Minecraft higher than release 1.6, the new launcher will automatically update LWJGL to newer versions, making the steps in this guide unnecessary.