MSFS is stuck in Windowed Mode plus the Clock is Displaying Wrong Time

Re live weather, read the banner at the top of every forum page.

Unless you have a whole lot of issues, I would not recommend a reinstall.
If your issues are due to saved settings, these same settings will be restored and you will be no better off.
A reinstall can often lead to more unwanted problems as well.
Did you follow the cloud save delete above?