I'm good at typing with 10-fingers, as I use a blank keyboard.
But I have a problem. I almost always use the left Shift key, even if the right Shift key would be better (same for Ctrl).
What I'm searching for is an application that blocks (and possible notifies) the wrong Shift key.
E.g.: I want to type a uppercase "W", "$", "!" ... and use the left Shift key, the result should be "w", "4", "1" ... and maybe a flash on the screen (that left Shift was blocked, because I should have used the right Shift key).
Platforms I use are GNU/Linux and Windows 7, both 64-bit.