I had the opposite problem. try going to "Tools"-"Options" on the view tab
check "Windows in Task Bar"

"Waterboy" wrote:

When I open an excel document, excel opens the document in the same instance
of excel. When you close excel, it closes all open workbooks. I would like
to be able to close the instance of excel that I am working in (by hitting
the top X) and continue to work on seperate excel documents that are open.
This works in Word, but not in excel. Any ideas on how to fix this one?
Thank you!