Certain cells to be entered before my userform can be triggered.

[danbates]

Hi,

I have a form that works in rows and row 5 is the first row with a clean in.
I have 3 different types of cleans and they are determined by what letter is in column B.
I want different cells to be entered within the cleans before the userform in column AP can be triggered.

Cleans are determined by A, B and C.

[TABLE="width: 200"]
<tbody>[TR]
[TD]Column B
[/TD]
[/TR]
[TR]
[TD]Type of clean
[/TD]
[/TR]
[TR]
[TD]A
[/TD]
[/TR]
[TR]
[TD]B
[/TD]
[/TR]
[TR]
[TD]A
[/TD]
[/TR]
[TR]
[TD]C
[/TD]
[/TR]
[TR]
[TD]A
[/TD]
[/TR]
[TR]
[TD]B
[/TD]
[/TR]
[TR]
[TD]A
[/TD]
[/TR]
[TR]
[TD]C
[/TD]
[/TR]
</tbody>[/TABLE]

and so on.

Here are the columns I would like to be entered before the userform can be triggered:

Clean A = E, M, AE.

Clean B = E, M, O, U, AE, AG, AM.

Clean C = E, G, I, K, M, O, Q, S, U, Y, AA, AC, AE, AG, AI, AK, AM.

I'd like a message box to alert them if they have missed one or more of the cells.

I hope this makes some sort of sense and any help would be much appreciated.

Kind Regards

Dan