Hide/Show rows based on drop down list

First of all THANK you to all of you!! You have helped me many times throughout the years and just want to say Thanks!! Now my problem. Have been seaching here and the web and cant get much to work at what Im doing. I have tried Form Control and Active X Drop downs and Combo Boxes and cant get anything to work.

What Im trying to do is if something is selected from the drop down it would then hide Rows 20:26 but if any other name is selected I would like it to unhide those rows 20:26. I have tried multiple VBA and can never get it to unhide or change with the drop down I always have to enter the number in the cell myself and the vba's work. I have attached an example.

Using Excel 2010