Hello, My name is ***** ***** I'll be assisting you. I'm sorry you're having problems.
This happens when there's an HDMI glitch between the Roku and the TV. Please try a basic reboot as follows:
1) Shut the TV off and unplug the Roku's power cord.
2) Remove and reconnect the HDMI cable on both ends- making sure it is secure.
3) Plug the Roku's power cord back in and turn the TV on.
Let me know what you see on your screen at that point- it should bootup normally and then work as it did.
If not, then I will need to know the model of the Roku you have (1,2,3 or Stick) and also the model number off of the back of the TV.
If you need further assistance let me know. Also, please do click a 3-5 STAR rating for my efforts before you go. That is how I am credited for my efforts by the site. You can follow up any time as needed at no additional cost.
Please review my reply and try those steps.