Excel spawning a new window when opening a file
 

If I lauch Excel.exe from my quick launch it opens a new window each time I
click it. However if I double click an .XLS file from MSexplorer (or MS
Internet Explorer) they all open inside the same window.
How can I control these opening behaviours?

Some of my users want each file opening in the same window, others like
seperate windows but very few like the mixed approach described above!

Excel 2003 SP2
Windows XP Pro

Rob.