Jock try this,

In a hidden column place the following formula:
=if(COUNTA($D1:$H1)=0,FALSE,COUNTA($D1:$H1)<3)

Copy formula down to all cells required. Amend conditons as required for the
TRUE/FALSE option.

Use Conditional Formating across columns to refer to hidden column to turn
cell colour to RED if all cells you want completed are not completed. Use the
TRUE/FALSE return to change cell colour. Once user completes all three
required cells, cell colour returns to normal.

Hope this is easy way out/sgl



"Jock" wrote:

I need to ensure that certain cells in every row are filled in by the user.
How can I add code to force data input into, say, columns D, E and H when
the user navigates to the next row? Perhaps a popup box informing the user
and highlight the empty cell(s) in yellow for instance? Can the user then not
be able to continue until the empty cell(s) are filled in?

Thanks,
--
Traa Dy Liooar

Jock