2013 excel - selection from drop down list makes certain cells inactive

Hello all, I want to create my excel sheet so that I have a drop down list with two selections in the top cell. When on of the selections is chosen then cells 5 to 10 become inactive and when the other selection is chosen cells 2 to 4 become inactive. by inactive I mean they cannot select anything in these cells as all cells will be drop down lists. Can anyone help as I have been trying to work this out for longer than I perhaps should've. Thanks