Open excel files in multiple instances

Question

When ever i open the excel files it opens as different windows of the same instance . Is there any way to open in multiple instances of excel ...  I saw some answes in forums which says about about unchecking 'Ignore other application that use DDE'
.. once i set that the excel file doesnot open again giving an error "there was a problem sending the command" ....
Could some one help me on this .. this is pretty urgent for me ...  i am using this in my vb.net project with process.start(file)  ...
i dont think i want to create an excel application and open the file in the code as i may not be able to release the com objects properly in my fuinctionality .... 

Answer 1

Try this one:
1. To begin, we go to the registry. Click START, and in the RUN command line type REGEDIT and hit ENTER or click OK. This will start the registry editor.
2. Navigate to the following key: HKEY_CLASSES_ROOT\Excel.Sheet.8\Shell\Open\Command
3. Double click on the (Default) instance over to the right. Right now this probably says something like:
If you have Office 2007 installed:
C:\Program Files\Microsoft Office\Office12\EXCEL.EXE /dde
Or, if you have Office 2010 installed
C:\Program Files\Microsoft Office\Office14\EXCEL.EXE /dde
Change this value to:
C:\Program Files\Microsoft Office\Office12\EXCEL.EXE /e "%1"
for Office 2007 and for Office 2010 change it to:
C:\Program Files\Microsoft Office\Office14\EXCEL.EXE /e "%1"
4. Navigate to the following key: HKEY_CLASSES_ROOT\Excel.Sheet.12\Shell\Open\Command
Again, double click the (Default) entry to the right and change
C:\Program Files\Microsoft Office\Office12\EXCEL.EXE /dde
to
C:\Program Files\Microsoft Office\Office12\EXCEL.EXE /e "%1"
When you exit the registry this should be all you need to do. Each time you double click on your Excel shortcut or type excel.exe in the command line a new instance of Excel is launched with the default spreadsheet.
Quote from:
http://blogs.technet.com/b/the_microsoft_excel_support_team_blog/archive/2011/09/06/opening-excel-in-multiple-instances.aspx
Max Meng
TechNet Community Support