This is not too hard of a script to write. HOWEVER what you are asking is when the user selects cell C16 to have it run. To my knowledge the only way to do this is with a worksheet change procedure. Meaning the code will run everytime there is a change to the worksheet. Even a selection change will cause it to run. This is not a slow process or anything but it does remove the ability to "Undo" commands. Because of this I dont like writing procedures that remove the undo functionality. If you can live without the undo I will write it for you however if you need the undo functionality then we would need to find a way for the code to run by the user clicking on a box or something like that.

Let me know

Thanks