screen is dark

Hi; I am a newby here and am looking for some assistance with KODI. I got the system up and running a couple of weeks ago but after a few days the system would not boot up or operate. I get a dark screen with the word xfinity for a few seconds then it goes to a dark screen. I have no way adjust the system and provide a log file. I have uninstalled 16-1 then krypton but when reloaded there is no change. There is a digital clock in the top left corner of he screen. If you need a screen grab pls email me and I will send one. Beyond that I have no controls. There is one strange symptom: if I randomly scroll the curser around, some images can be seen below the dark screen.
Also there is an error message that says exception caught on main loop exiting.

Any help would be great !]
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