Excel - Create a Dropdown List in a Cell

This whole content is from this Microsoft webpage: http://office.microsoft.com/en-us/excel-help/create-or-remove-a-drop-down-list-HP010342357.aspx

I've just copied it here for ease of use.

1. To create a list of valid entries for the drop-down list, type the entries in a single column or row without blank cells. For example:

	A
1	Sales
2	Finance
3	R&D
4	IT

 NOTE    You may want to sort the data in the order that you want it to appear in the drop-down list.

2. Select the cell where you want the drop-down list.

3. On the Data tab, in the Data Tools group, click Data Validation.

4. In the Data Validation dialog box, click the Settings tab.

5. In the Allow box, click List.
6. Now select the cells that hold your list.
7. Make sure that the In-cell dropdown check box is selected.

8. To specify whether the cell can be left blank, select or clear the Ignore blank check box.