Bill-
1. one possibility is that there is a macro button on the first file you are oppening that refers to a macro located on the second file that opens. or maybe a range name on the first sheet that refers to the second sheet.
Try opening the first file, and if a second file opens, go back to the first file and from the menu bar select Edit>Links... and see if there are any links to the second file. If 'Links...' is greyed out, there are no links. If 'Links...' is not greyed out, and you can't determine what is linked, the is an add-in at the Microsoft site to delete links.
2. Look in the Excel start up folder (usually C:\Program Files\Microsoft Office\Office\Xlstart) to see if the file that keeps opening is there. Also, from the menu bar select Tools>Options>General and see if there is a folder listed under 'Alternate startup file location', and see if the rogue file (or any excel file) is in this folder.
HTH
Mark
Mark may have hit it on the head! The file was in my
alternate startup directory. When I moved it, it stopped
coming up. Many, many thanks, Mark!