Windoes movie maker plays sound but no video?

ok so before I start, I know I should be using another software to edit videos for my gopro and or have a better computer than what I have, (old and sucks) but going to why you are here…
I have done several videos on an obstacle course and have uploaded all onto WMM to edit them. All my videos were able to properly convert to the format or whatever so that WMM can edit and play them. One video did process just like the others but never could play at first. It played but no audio or video, just played with a black screen. After some time, it finally played sound but no video. All other videos play fine but this one did not. Also it is 13 minutes but I think I have uploaded another that was longer so I dont think it may be length. Then again I am not sure.

so what should I do? I need this video clip

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