I'll never get the hang of this...:-(

I had a similar problem recently that was solved in this ng (Thanks Dave:-)
but have a related problem that I thought I could solve by applying the same
logic - alas it was not meant to be for me :-(

I want to use Conditional Formatting to achieve the following - if the value
in Cell H15 is lower than 75 then colour it red.

This I can achieve quite easily by using the following in Condition 1:

If Cell Value is Less Than 75 then Format Pattern Red

However I do not want the cell to be coloured Red if there is no value in
there at all - I only want to be able to turn the cell red after I have
input the value and that value is less than 75

Obviously I need to test for input in H15 prior to checking if it is below
75 and invoking the colour change if it is - leaving no change if it has no
value or is 75 or above.

I have tried using a COUNTA but cannot seem to get it to work.

Can some kind soul help me out on this one (again) please?

--
Thanks & regards,
-pp-