If you have already downloaded a new Keplerian element file, you can use Nova for Windows' drag-and-drop to update its internal satellite database.
Simply drag the file, whatever its name is, from its current location to anywhere within the Nova for Windows program or its icon on the Windows desktop:
Place the mouse over the file's icon (on the windows desktop or from within Windows Explorer) and press the left mouse button.
With the mouse button depressed, move the mouse to Nova. You will see the mouse cursor change shape as it moves over Nova's domain.
Release the mouse button.
If the file contains valid Keplerian elements (AMSAT or NASA format), Nova will read the file and update itself. If the elements cannot be read, then you will receive a message informing you of that fact.