Macros to Run based a specific cell value

So I need some help.

I have message boxes that I want to open when the value of D2 is = to different values.

I have the message box codes written but I am unable to link these to the cell values.

ie. If D2 = Test , messagebox 1
If D2 = Actual, messagebox 2
If D2 = Old, no message.

the values from D2 are in a conditional list and the message box should open each time the value in the cell changes.

Thank you in advance.

Alan,

Thank you for you quick response. The value in D2 is a conditional list. I want the message to pop up anytime the value in that cell is changed from the list. The message box does not open when I change the value in the cell.

Thoughts?

Thank you,