Keyboard input problem.

In various scripts, including common ones such as the basic FPS Controller, I am not able to get keyboard control to consistently work.

When I key some movement direction (eg - forward), continue holding that movement key and key some other movement direction briefly (eg - left), the original direction stops. So if I'm moving forward, and strafe briefly, my forward motion stops.

This seem like a dumb mistake on my part, but I can't figure it out.

Could it be that you have a keyboard which is behaving in a non-standard way? Are you able to try plugging a different keyboard into your computer to test this?

I just tried a new scene. It works ...

What version of unity are you using ?

Try to display your Inputs values ? See if your keyboard release the forward key when you press left.

function OnGUI(){
    GUI.Label(Rect(10,10,Screen.width,30), Input.GetAxis ("Vertical").ToString());
}