Help for coding

Hello, I need help to solve the error code BCE0020: An instance of type ‘UnityEngine.Rigidbody’ is required to access non static member ‘AddForce’
Thank you kindly correct my script:
function Update ()
{
InputPC ();
}

/ / ------

InputPC function ()
{
/ / we will put the controls right and left blocking the making of both at the same time
if (Input.GetKey (“left”))
{
/ / adding a rigid force left to be independent of the ball
rigidbody.AddForce (Vector3.right-);
}
else if (Input.GetKey (“right”))
{
/ / the same thing right
rigidbody.AddForce (Vector3.right);
}

/ / the same thing but to jump up and down
if (Input.GetKey (“up”))
{
rigidbody.AddForce (Vector3.forward);
}
else if (Input.GetKey (“down”))
{
Rigidbody.AddForce (Vector3.forward-);
}
}

UP help me please

your last rigidbody.AddForce, its need to be lowercase R you have it uppercase. And plese use code tags the next time http://forum.unity3d.com/threads/143875-Using-code-tags-properly