Help!

I have this huge worksheet with all kinda of formula,look up and dropdown menus.

Several of the columns need drop down menus, however I have all ready used the Validation to create a error message with cusom formulas.

I think I have seen that there is a webpage that tells how to create the dropdown menus in VB.

My drop down menu are simple
Worksheet name: 1
HB or a blank cell would go into columns BC17:BC160,BD17:BD160
EXPRESS or a Blank cell would go into colums BE17:BE160,BF17:BF160
HBX or a Blank Cell would go into coulumns BG17:BG160,BH17:BH160