how can i auto target Gameobject on startup

i know im doing this really wrong help if possible (trying to set the target automatically on start up to the player (PC)
but unsure how i know every thing i has work when i drag the object to the target but i need to auto target

///
/// EnemyAttack.cs
/// Oct 20, 2010

///
/// This is a very basic Mob Attack script that we are going to use to get use to coding in C# and Unity
///
/// This script is ment to be attached to a mob, or a mob prefab
///
using UnityEngine;
using System.Collections;

public class EnemyAttack : MonoBehaviour {
public GameObject target;
public float attackTimer;
public float coolDown;

public string playertarget;

// Use this for initialization
void Start () {
	attackTimer = 0;
	coolDown = 2.5f;
	
	PC = GameObject.FindGameObjectWithTag("PC");
}

// Update is called once per frame
void Update () {
	if(attackTimer > 0)
		attackTimer -= Time.deltaTime;
	
	if(attackTimer < 0)
		attackTimer = 0;
	
	if(attackTimer == 0) {
		Attack();
		attackTimer = coolDown;
		
		PC.PLAYER_TAG("PC")// i know im doing this really wrong help if possible (trying to set the target automaticly on start up to the player (PC) 
								//but unsure how i know every thing i has work when i drag the object to the target but i need to auto target
	}
}

private void Attack() {
	float distance = Vector3.Distance(target.transform.position, transform.position);
	
	Vector3 dir = (target.transform.position - transform.position).normalized;
	
	float direction = Vector3.Dot(dir, transform.forward);
	
	if(distance < 2.5f) {
		if(direction > 0) {
			PlayerHealth eh = (PlayerHealth)target.GetComponent("PlayerHealth");
			eh.AddjustCurrentHealth(-10);
		}
	}
}

}

change this

 PC = GameObject.FindGameObjectWithTag("PC");

to this

target = GameObject.FindGameObjectWithTag("PC");

get rid of this

PC.PLAYER_TAG("PC")