There are two ways to do this: You can freeze the first visible row, or you can freeze a set of rows. Keep in mind that this doesn't have to literally be the top row in your spreadsheet - this ...
To fix this, navigate to the "View" tab in Microsoft Excel, and click on "Unfreeze Panes" if you see that option enabled. Also, make sure the setting remains default for the "Freeze Top Row" and ...