[Solved] Back button on Roku not working

This past Thursday night all of the back buttons on my five roku remotes started working again. They were still working Friday and I assume - though I have not used the Roku again today, Saturday that they are still working.  Before Thursday they were not working along with the back button on the Roku App.  When I turned the Roku on first on Thursday - the screens were slow to load, the picture was dull -  not as bright as it usually is  and the back button was still not working.  I checked for updates and the update screen would not load - every thing on the Roku was slowed down. I unplugged the Roku (which I had done before when we discovered teh back buttons not working - to no avail) - and when I plugged it back in again the Roku started with its usual bright screen - and it was no longer slow.  The only thing I can assume was that before I unplugged it some update was taking place. And when tried the back button on channels it was not working with before - all worked!  Something was done on Roku's end to fix this. I am not sure why others are not finding theirs fixed!