Article in English: This may be located on your Desktop, in your Start menu, or in your Applications folder.  If you don't have the Chromecast app installed, you can get it from cast.google.com/chromecast/setup/  This method only works if you can connect to your Chromecast. If it is not appearing as a selectable device, click here. If you have multiple Chromecasts on your network, you will need to select the one you want to make changes to. Settings button. Factory Reset button. Click Reset to confirm. This will reset your Chromecast to its factory settings. You will need to setup the Chromecast dongle again to use it.

Summary in Chinese:
打开电脑上的Chromecast程序。 选择你的Chromecast。 点击.设置 按钮。 点击.恢复出厂设置 按钮。