function Start () {
    if (Application.platform == RuntimePlatform.WindowsPlayer)
        print ("Do something special here!");
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Start() {
        if (Application.platform == RuntimePlatform.WindowsPlayer)
            print("Do something special here!");
        
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Start():
        if Application.platform == RuntimePlatform.WindowsPlayer:
            print('Do something special here!')