I have an older model Roku/Hitachi TV. It is about7 years old. I was having trouble adding new streaming channels, so we bought a new Roku stick. We added it to HDMI1 slot but we can't get it allow us to connect to our WiFi. The TV is not connected to cable. We can't see how to remove the stick that came with the TV so we can use the newer one. Any help will be greatly appreciated.