The following would work for Win7 64 bit,(right click excel and open in new instance submenu)
Open a notepad and paste the following and save it as:- Excel OpenInNewInstance.reg
and right click merge…. you are done.. right click your excels and open in new instance
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\OpenInNewInstance]
@="Open In New Instance"
[HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\OpenInNewInstance\command]
@="\"C:\\Program Files (x86)\\Microsoft Office\\Office14\\EXCEL.EXE\" \"%1\""
[HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\OpenInNewInstance]
@="Open In New Instance"
[HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\OpenInNewInstance\command]
@="\"C:\\Program Files (x86)\\Microsoft Office\\Office14\\EXCEL.EXE\" \"%1\""