I have recently realized that when I open multiple documents in Excel they all show up separately on Taskbar but show up in the same window of Excel. This can be very aggravating for anyone who works with multiple documents and multiple monitors. After becoming fed up with Excel I did some research online and found a solution.
Choose XLSX (XLSX for 2007 or XLS for 2003)
Go to Advanced
Uncheck “browse in same window” in advanced window.
Then highlight Open
Make sure in the Action box it says &Open
Copy one of the following and paste into “application used to perform action” (Check whether current path has OFFICE11 or OFFICE12 then copy and paste one of the following:
“C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE” “%1″
“C:\Program Files\Microsoft Office\OFFICE12\EXCEL.EXE” “%1″
Check the box next to use DDE
Remove anything that is in DDE Message box and DDE Application Not Running box.
Make sure the application box says: EXCEL
And in the Topic box it says: System