rollaball ball wont move

already consulted several posts on here, none work here’s my script

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour
{

public float speed;

private Rigidbody rb;

void Start()
{
    rb = GetComponent<Rigidbody>();
}

void FixedUpdate ()
{
    float moveHorizontal = Input.GetAxis("Horizontal");
    float moveVertical = Input.GetAxis("Vertical");

    Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

    rb.AddForce(movement * speed);
}

}

Has @haruna9x said, you need to set the speed value to anything higher than 0. Either go to the inspector and change it, or change it in the code, such as

void Start ()
{
     rb = GetComponent<Rigidbody>();
     speed = 1.0f;
}

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour
{

public float speed;

private Rigidbody rb;

speed = 1.0f;

void Start()
{
    rb = GetComponent<Rigidbody>();
}

void FixedUpdate()
{
    float moveHorizontal = Input.GetAxis("Horizontal");
    float moveVertical = Input.GetAxis("Vertical");

    Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

    rb.AddForce(movement * speed);
}

}

currently looks like this
error reads "Assets/script/playermovement.cs(4,14): error CS0101: The namespace global::' already contains a definition for PlayerController’
"

problem fixed!!!