Data Validation should not accept blank input

[gord9b]

I have a cell with a Data Validation with a list having the Source as a named range on the worksheet. However, if I blank out the cell, it is accepted. I tried selecting the 'IGNORE BLANK' button on the Data Validation form and unselecting it. Nothing works. How can I get this cell to reject a blank input and only allow the listed items?
Second, This source list is selected with an '=INDIRECT(A17)' statement. If A17 is changed, how can I blank out this cell(D17), thus forcing the person to select a valid input from the new list, considering the fact, the list will not accept a blank input if I can get an answer to my first question.

 

[Chas17]

Place "<>0" as one of your cells in the named range.
i.e. the cells in range are a1,a2,a3
a1 = <>0
a2 = 1
a3 = 2

It will then not accept zero.
Please let me know if this is what you meant.
Thanks

 

[gord9b]

Sorry but this is not what I want. When the cell (D17) is selected and I type any invalid input, an error message prompts me to correct it. If I just blank out the cell, I can continue without any error message. I want the cell to not accept blanking out of the input without an error message popping up.