Making a cell mandatory if the preceding cell has values without VBA

[Fruitloopy]

Hi All

I have a customer order form we send out to customers for them to choose from a range of products we sell and confirm the quantity they need. The problem is these order forms come back to us sometimes missing the quantity and we have to waste time contacting the customer to confirm the quantity of the product we need.
What I would like to do is make the Quantity cells (H29 to H101) mandatory IF they have chosen a product from the drop down menu in cells (A29 to A101). I don't want to use VBA because of macro support.
Can a formula do this? Can it at least make the cell on the row where quantity is missing go red or present a popup message?

Here's a screenshot of the order form:

Thanks

 

[mart37]

Can it at least make the cell on the row where quantity is missing go red

You can use Conditional Format.

 

[blbat]

Without VBA I don't think you can make it "Mandatory" to enter a cell value.

I would use the following in your column "H" (H29):
=IF(ISBLANK($A29)=FALSE, "Please Enter Quantity", "")

Then you can conditional format H29 to turn red by testing for the text: "Please Enter Quantity"