From memory, but try Tools, Options, View, Show in windows (or similar)

Erika wrote:

I need to open several workbooks in different windows. I am working with
Excel 2003, it use to work this way but I must have changed something.

I do not work with dual monitors, I just have 4 different workbooks and I
would like them all to display on my taskbar so I can click on them.

I do not have the option to group similar programs checked.