The top part of the window is called ribbon. It is where all the options are available.
When the ribbon goes invisible and does not show any feature, it is most likely because of corrupt display driver or corrupt windows files. This issue can be visible in File explorer, Microsoft Applications, Browser, ETC.
Update the display Drivers.
Right Click on start button>Device Manager>Display adapters.
Make sure you are using same adapter in case of multiple displays.
Right click on the adapter and update the driver.
Try installing the Driver automatically. If it does not fix the issue, try installing the drivers by downloading it from the browser.
Fix the corrupted Windows files.
>Cleaning up corrupted Windows files most likely resolves this issue. perform below steps to clean up the corrupt file.
>Open the command prompt as Administrator and type “SFC /SCANNOW.
Also, in the CMD Type “DISM /Online /Cleanup-Image /CheckHealth” after the scan is completed and the corrupted files are fixed.
>Restart the computer and check the ribbon.
Install the windows and start from the scratch if the ribbon issue is not resolved.