Question : One vs. More Than One Instance of Excel

On an XP machine, when you (a) open an Excel 2007 spreadsheet in Windows Explorer and then subsequently (b) open an Excel 2007 spreadsheet using the Microsoft Excel/Office "open" button in the top left-hand corner, this creates two separate instances of Excel.  I can tell this by looking at the "Processes" tab of Task Manager and seeing two "Excel.exe"'s.

But, when I conduct the same tasks on a Windows Server 2003 machine, only one instance of Excel is shown in Task Manager.  Likewise, on a Windows Vista machine, only one instance of Excel shows.

Why would one machine show more than one instance of Excel while other machines only show one instance--even when the machines perform the same tasks mentioned above?

Is there a way to "force" Excel to only have a single instance?  I want put this single instance in place on this XP machine.  (Does it have anything to do with how Excel was installed on this XP machine, originally?)

Answer : One vs. More Than One Instance of Excel

This is somewhat related.
If you have Excel set up to start a new process for each Sheet, it will do what is happening with your XP machine.
Be default, the behaviour is per the Vista/7 machines.

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