I would like to create a macro which works as below but I can't quite see how to do it . . .

• If another Excel workbook is not open, save the active workbook, close it and quit Excel
• If another Excel workbook is open, save the active workbook and close it - leaving the other workbook(s) open.

I know how to do all of this, except how to detect if another Excel workbook is open.
Thanks for any help