The easy way to open two or more excel files separately.
I use Windows 7 and Excel 2010. This is what works for me (just figured it out):
1. Create a shortcut of Excel application on Desktop
2. Open your first Excel file and place it on the screen you want
3. Open a new Excel file from the Excel icon on Desktop or on Program files.
4. The new file will open on top of the one you have already opened. Drag it to the other screen
5. Drag the icon for the second Excel file INTO the new (blank) Excel document
Voila! Two separate screens.