If B6 = "NO" input "COMPLETE REASON" in B7, then if C7 has text make B7 blank

Good day.

Please help me if you can.

I have a problem,

I have a table - columns A/B/C - Column B will have YES, NO or N/A - If NO then the row below must automatically get text "Complete Reason" - if reason is typed in in Column C then the "Complete Reason" must disappear.

That is the first part. Once that is done, I need a conditional formatting or setting that if the person did not select YES, NO or N/A then they cannot proceed completing any of the further YES/NO/N/A - This way trying to force them to complete the form properly.

Column B currently has Data validation list to select the YES/NO/N/A

If anybody can help me please. I have atttached a file and hope you can see it.