key word void cannot be used in this context

using UnityEngine;
using System.Collections;

public class PlayerIO : MonoBehaviour {

RaycastHit hit;
int MaxBuildDist = 10;
public Transform RetAdd;
public Transform RetDelete;
Color Block_Color = Color.blue;
bool Block_Menu = false;

// Use this for initialization
void Start (){
	RetAdd = GameObject.Find("RetAdd").transform;
	RetDelete = GameObject.Find("RetDelete").transform;
}

// Update is called once per frame
void Update (){
	if (Input.GetKeyDown(KeyCode.E))
		Block_Menu = !Block_Menu;
	if (Block_Menu)
		Time.timeScale = 0;
    if

	(!Block_Menu){
		if(Physics.Raycast(Camera.main.ScreenPointToRay(new Vector3((Screen.width / 2), (Screen.height / 2), 0)), out hit, MaxBuildDist)){
		RetAdd.GetComponent<Renderer>().enabled = true;
		if(hit.transform.tag == "Block"){
			RetAdd.transform.position = hit.transform.position + hit.normal;
			RetDelete.transform.position = hit.transform.position;
			RetDelete.GetComponent<Renderer>().enabled = true;
		}
		if(hit.transform.tag != "Block"){
		    RetDelete.GetComponent<Renderer>().enabled = false;
			RetAdd.transform.position = new Vector3(hit.point.x, hit.point.y + 0.5f, hit.point.z);
		} 
	if(Input.GetMouseButtonDown(0)){
		GameObject block = (GameObject)Instantiate(Resources.Load("Block01"), RetAdd.transform.position, Quaternion.identity);
			block.GetComponent<Renderer>().material.color = Block_Color;
	}
		else if(Input.GetMouseButtonDown(1) && hit.transform.tag != "Floor"){
			Destroy(hit.transform.gameObject);
	 

}
else{
	RetAdd.GetComponent<Renderer>().enabled = false;
	RetDelete.GetComponent<Renderer>().enabled = false;
}

}
}
void OnGUI(){
if(Block_Menu)
Block_Menu_GUI();
}

	void Block_Menu_GUI(){
		GUILayout.BeginVertical();
		if(GUILayout.Button("Green"))
		Block_Color = Color.green;
		if(GUILayout.Button("Red"))
			Block_Color = Color.red
		if(GUILayout.Button("Blue"))
			Block_Color = Color.blue
		GUILayout.EndVertical();

}
}

sorted it