Hi:
I've had luck with the following:
Instead of "Exporting to a Spreadsheet", a command from the Actions Menu, switch to "Edit in Datasheet" from the same menu. Assuming that you have MS Access installed on your PC, your page will appear like an Excel sheet/grid.
Select the vertical expansion "bar" way over at the right of the list and select "Query List with Excel". This will create an Excel sheet that's connected to your List. Save the Excel sheet.
Finally, using Excel's "External Data" toolbar (View/Toolbars), you can use the "Synchronize List" command to move data from the Excel sheeet back to the List.
Having MS Access installed, is the key.
Charlie