Only allowing one open workbook in excel
 

Hi Legends,

I need to stop users launching excel spreadsheets into my workbook. For example, if an e-mail has an excel attachment and the reader launches the attachment, or if the user opens an excel file from Explorer, I need to ensure a new application of excel loads up to view it and does not just launch in the excel application that is already running with my workbook in it. My workbook has links to other applications and it all crashes if a new workbook is opened (even a new workbook! I have got round that by changing the menus so opening worksheets from my workbook invalid). I can't run a macro to close the new workbook as excel hangs before the macro is executed. Is there a property you know of that I can turn off/on in the workbook_open of my file that will stop any new workbooks loading in its existing application?

I hope the above is clear! If not pls ask me to explain in more detail. Thanks.

Only allowing one open workbook in excel
 

Don't panic! Found it out myself

For anyone interested: In Windows Explorer:
under View - Options - File Types for Microsoft Excel Worksheet (double click it), Open (double click it), deselect the use DDE tick box

Hoorah