Sounds like you could use Data Validation for this. Select the cells you want to appear as entries in the drop-down box and click on insert-name-define and type in a name in the top box (eg myList). Select the cell or cells that you want the drop-down box to appear in and click on Data-Validation. Change the allow box to List and in the Source box at the bottom type in
=myList
then just click on OK and you're sorted.