Hello all excel gurus!

I am hoping someone can help me with the following:

I have a column containing data validation so that when someone clicks on the cell they can only choose from the drop down list.

The following are the choices in the drop down menu: as,ba,cu,dc,ef,f,gd,hy,ie,jl

What I want to do is, when someone choose "dc" and only '"dc" a pop up message appears. ( I know I can get a pop up w/ data validation, but it will pop up for every letter and only when incorrect data is entered)
I am hoping I can get some sort of VBA script for a pop up, whose text I can edit..


Someone please help....


Thank you soooo much!