Mike,

You might check from Windows Explorer | Tools | Folder Options | File
Types, scroll to the XLS file association, and then click on the
Advanced Button, then select the "Open" Action, then click the Edit
button. Chances are it has a /e startup switch which defeats the
automatic new workbook opening ... as in:

"C:\Program Files\Microsoft Office\Office\Excel.exe" /e

or maybe like this for me in Excel 2003

C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /e "%1"

HTH,

Jeff