python编写selenium自动化脚本时报错

本人超级菜鸟一枚 目前自学中 python环境什么的应该都按照教程配置好了 脚本也是照抄的 但还是报错了。。。求大神解答
脚本如下：
# coding=utf-8
from selenium import webdriver

driver=webdriver.Firefox()
driver.get("http://www.baidu.com")

driver.find_element_by_id("kw").send_keys("selenium2")
driver.find_element_by_id("su").click()
driver.quit()

报错内容如下：
Traceback (most recent call last):
File "C:\Users\Administrator\AppData\Local\Programs\Python\Python37\lib\site-packages\selenium\webdriver\common\service.py", line 76, in start
stdin=PIPE)
File "C:\Users\Administrator\AppData\Local\Programs\Python\Python37\lib\subprocess.py", line 775, in __init__
restore_signals, start_new_session)
File "C:\Users\Administrator\AppData\Local\Programs\Python\Python37\lib\subprocess.py", line 1178, in _execute_child
startupinfo)
FileNotFoundError: [WinError 2] 系统找不到指定的文件。

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "C:/Users/Administrator/Desktop/baidu.py", line 4, in <module>
driver=webdriver.Firefox()
File "C:\Users\Administrator\AppData\Local\Programs\Python\Python37\lib\site-packages\selenium\webdriver\firefox\webdriver.py", line 164, in __init__
self.service.start()
File "C:\Users\Administrator\AppData\Local\Programs\Python\Python37\lib\site-packages\selenium\webdriver\common\service.py", line 83, in start
os.path.basename(self.path), self.start_error_message)
selenium.common.exceptions.WebDriverException: Message: 'geckodriver' executable needs to be in PATH.