This is a minor annoyance at best as it adds unnecessary mouse-clicks every
time I try to open an existing spreadsheet unless the Excel application is
already running.

I've recently upgraded to Excel 2007--I never had this issue with 2003. When
I open an existing spreadsheet, the application opens but the file does not
come up. If I click on the RIBBON, the spreadsheet appears as if it were
hidden; if I click on another window or ALT+TAB back and forth, the
spreadsheet appears. If Excel 2007 is already running when I open on a
spreadsheet it comes up fine.

I've gone through the Excel Options menus but have found nothing that might
refer to this issue. Any assistance you can provide on this would be greatly
appreciated!