Data Validation: help creating error message based on certain conditions

[HeyInKy]

I am working on a sheet in which users will respond to 9 questions, 7 of which are "Yes/No" and 2 are numerical answers. For the response cells, which occur in D8 thru D16, I have used Data Validation to restrict answers, which then result in a point being awarded or not being awarded in columns E-G.

If the answer to question 1, recorded in D8, is "Yes," then the answer for question 2 can be either "Yes" or "No" - and is input in D9. By the way, I have used =COUNTIF(D9, "Yes") in G9 and =COUNTIF(D9, "Yes")*2 in G8 to score the response (the times 2 because that question is weighted and a yes response is worth 2 points).

My problem is, under the rules of the questionnaire, if D8 is no then D9 must also be no (the first two questions may be answered yes/yes, yes/no, or no/no, but not no/yes). I would like an error message to appear if the user attempts to answer no/yes, but can't seem to get it. I'm trying to not use VBA because I know very, very little about that - but I could go that route with easy, step-by-step directions.

For now, my work around was simply creating =IF(AND(G8=0,G9=1),"Error"," ") in H9 to alert the user of an error, but this does not prevent them from continuing anyways.

[Tony Valko]

What you could do is link the validation in cells G10 onwards to the result of the formula in cell H9.

If H9 = ERROR don't allow any entries in cells G10 onwards.

Something like:

=AND(H$9<>"ERROR",OR(G10="Yes",G10="No"))

=AND(H$9<>"ERROR",OR(G10=some_number>=this,G10=some_number<=this))