My work revolves around Excel and with my dual monitor setup it makes it a hell of alot more productive if i can have one Excel instance open on one monitor and the next on the other monitor.
But Excel always opens your second document as a worksheet of the first one and you can thus not seperate them and drag one to the extended montitor.
I found a blog on online tech tips that explains how to make two seperate excel instances possible and it works like a bomb.
Simply download THIS file. Extract it on your PC and run the file "Add Open In New Excel Instance.bat"
After this registry file has been applied you will be able to right click on any Excel file and select "Open in New Excel Instance" and you will have two seperate Excel instances!