You can use conditional formatting to highlight cells that contain the same information as what you typed in a cell.

Select the range that contains the list of last names, then go to Home|Conditional Formatting|New Rule.

Select "format only cells that contain" from top and enter cell value > is equal to > and then =$A$2

Click Format and choose from the Fill tab.

Click Ok, then Ok again to apply.

Now type a name in A2 and see if it hightlights the name in the list of names.