First, you don't need the =sum() function. You're not adding multiple cells.
You're just retrieving the value from a cell in that workbook.

Second, I'd guess that you don't have both workbooks open in the same instance
of excel. Open excel and then use File|open to open both files.

(Your formula includes the drive and path. These wouldn't be included if both
workbooks were open in the same instance.)

Teri wrote:

I have two workbooks that I was trying to link together. Workbook 1 holds
the data and the information went on to workbook 2 but it's not updating when
you change the data in workbook 1. I have something wrong in my formula
=SUM('C:\My Network Places\TMFolder\2009 Trip Points\[2009 Trip Points
A-B.xls]Air Mech'!D36) What should I be using. Please keep it simple, not
an advanced user. thanks.

Teri

--

Dave Peterson