Maybe it's just:
tools|options|View tab|uncheck windows in taskbar.

If it's not:

Sometimes one of these works when you're having trouble with double clicking on
the file in windows explorer:

Tools|Options|General|Ignore other applications (uncheck it)

--- or ---

Close Excel and
Windows Start Button|Run
excel /unregserver
then
Windows Start Button|Run
excel /regserver

The /unregserver & /regserver stuff resets the windows registry to excel's
factory defaults.

Maybe one of these will work for you.

StephanieH wrote:

My entire system crashed a couple days ago. The IT guys reimaged the pc and
I've lost a lot of settings.

Now, Excel always opens a new session anytime I open a workbook. In other
words, each workbook appears separately on my task bar. I'd like to have a
single session of Excel with all the workbooks in it. How do I force it to
open the workbooks in the same session/instance?

--

Dave Peterson