Opening Multiple Copies of Excel in VBA

This probably sounds an incredibly stupid question, but I have been asked to develop an app for a client that uses Excel but is not to behave like Excel. I’ve gone through the process of removing the menu and toolbars etc, but I want to be able to open another Excel rather than use the copy that may be open on the user’s PC. Basically I want another Excel open when the file is opened and on exit take close that version of Excel down. Now I know I can use application.quit to get out, but is there a way that I can create a new instance of Excel?

Thanks, sorry for the rambling but my mind is going mad thinking about this!

Dean