I have a Roku 2. I can only get the Roku screen advertising their Roku TV. No matter what I do I can't get off of this screen and back to my Roku home page, where all of the alternative channels are listed.
Does unplugging the Roku from its power source for a few seconds allow you to get to your Roku home screen when the system restarts?
You need to be more specific about your model Roku. There are two different Roku 2 players, and three more that have 2 in the model name. Not all of these are still supported by Roku, and all five of them are going to have issues with some of the latest channels. The absolute newest Roku 2 model is over 5 1/2 years old, and the hardware is far less capable than the latest players.