Let's assume that column "A" contains data and column "B" contains a
drop-down list that consists of simply "Yes" or "No".

Now let's assume that there multiple rows, simply for the sake of this
question.

If the cell of column "A" in any given row contains data, then the user is
to be able to use the drop-down in the cell adjacent in column "B" to select
"Yes" or "NO"... business as usual.

HOWEVER, if the cell of column "A" in any given row contains a zero, then I
want the drop-down in the adjacent column "B" to be disabled and the user to
not be able to enter any data into the cell.

Basically I want the adjacent cell in column "B" to display either a
drop-down selection (if there's data in the adjacent "A" cell), or a value of
zero if the adjacent "A" cell has a value of zero.

Is this possible, and if so, how do I do it?

Thank you in advance!
--
I''m just a simple man, trying to make my way in the universe...