Q5 Pro won't play video anymore

[JBMouse]

Can anyone solve this:
I haven't used the Q5 pro for a while, but I went to play a video file off USB stick, and nothing, just a blank screen, and I cannot back out of it, can't get to home screen or anything, except the box will switch off from the remote. I re installed custom firmware 2.1.4, updated Kodi to 18.5, youtube, chrome etc, and as before, no type of video file will play. I can play youtube OK, but both Kodi and mediaplayer just give me a blank screen, and no way to get back to home screen.
I am hoping someone, probably pcristi, can resolve this, thanks in advance.