I think you are still giving very little detail. Try to be more active, and not just reply to specific questions if you want help. Your initial question was short of "Fusion isn't working, please help me fix it." and then expecting to receive replies on how to fix your problems with no further details from you.
* Which specific OS are you using?
* Has this always happened, or did start happening at some point? Did you just install Fusion 360 for the first time?
* If you go to the question mark in the upper right corner of Fusion and select About, what does it say (Fusion and OS version)
* Did you install Fusion from Autdesk's site or did you download it from a pirate site? Sorry for asking, but some people seem to think it's ok to use pirated versions. I'm not accusing, just making sure since the behavior seems so odd.
* Can you provide a video of opening a file, showing the complete Fusion UI, like @jhackney1972 suggested?