If you have a workbook you've previously saved that you would like to work on, you must open the file first, before you can make any changes. Follow these steps to open an existing workbook:
Open the File menu and select Open , or click the Open button on the Standard toolbar. The Open dialog box shown in Figure 1.6 appears.
Figure 1.6. Use the Open dialog box to locate and open an existing Excel workbook.
If the file is not located in the current folder, open the Look In drop-down list box and select the correct drive and folder.
Select the file you want to open in the files and folders list.
To see a preview of the workbook before you open it, click the Views button and select Preview . Excel displays the contents of the workbook in a window to the right of the dialog box.
Click Open to open the currently selected workbook.
Recently Used Workbooks If the workbook you want to open is one of your four most recently used workbooks, you'll find it listed at the bottom of the File menu. It will also be listed at the top of the New Workbook task pane (if the task pane is active).