I have a Roku 4 system, a gift from friends. Within the last 1-2 days, when I choose a channel, the sound remains OK, but all that I can see is a blue screen. It starts with the "messages". The images of the channels I can access return when I return to Home. The connections appear to all be OK.
I have also had problems with the remote--the AA batteries get drained within about a week-10 days after I put them into the remote.
Is the issue issue you are experiencing only happening on a specific channel, or on all channels that you are watching?
Try removing the channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel back once more. Does this clear up the issue you are seeing?
If you are having issues with your remote draining the battery, please send me a PM with your Roku account email address, and include the serial number of the Roku device from Settings>System>About. I'll be able to assist you further from there.