A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I use Windows 7 and this is what works for me (just figured it out):
1. Open your first Excel file and place it on the screen you want
2. Open a new Excel file from the Excel icon
3. The new file will open on top of the one you have already opened. Drag it to the other screen
4. Drag the icon for the second Excel file INTO the new (blank) Excel document
Voila! Two separate screens.