Fuga
If the other workbook is already open, type the equals sign "=" as you would to start a formula, then click on the cell you want to reference, then press Enter to complete the formula. The contents of the referenced cell will be displayed. If the other worksheet is then closed, Excel will automatically adjust the formula to look it up from the file on disk.
Do it this way so that you see how the syntax works. Once you understand it, you should be able to create the formulas without having to open the other file first.
As a quick reference the syntaxes are:
For an open workbook - =[<Workbook Name>.xls]<Sheet Name>!<Cell Reference>
e.g. =[Projectors.xls]Sheet1!$C$10
For a closed workbook - ='<Path>[<Workbook Name>.xls]<Sheet Name>!<Cell Reference>
e.g. ='D:\My Documents\[Projectors.xls]Sheet1!$C$10
HTH
Rod
