My zoom app doesn't remain on my PC - I have to reinstall it before every meeting.

Hello! For the recent week or so I am facing the problem! After te meeting ends the zoom app disappears of my computer! Every time I have to re-install it again before the meeting starts. It is also impossible to download the app from the Microsoft store- it sais that it cannot install the app(( 
The worst thing is that I also cannot convert the video saved on my computer. PC cannot find the app to convert them with! 
Please help!