I am currently working on a sheet whereby we need to tell users to not fill in a cell based on previous selected values. e.g. Column A Row A user selects item from droplist; based on value selected user does or does not need to enter free-text into Column B, Row A. Is there any way Excel can tell the user to not fill in a cell if not needed based on selected value (coloring cell, or populating text in cell "N/A", anything like that). My use case involves two drop-lists (Col A, Col B - B values dependent on A's selection); with 20 free-text columns after that (user only needs to fill out some of these columns based on combination of A & B's selection). Each row may have a different combination between A & B (but same drop-list values).
It sounds like you could use an OR() statement to satisfy your conditional formatting requirements. You could format those cells that the conditional formats are true as black filled cells to defer the users from inputting information into those cells. Without seeing a sample of your data, however, it would be difficult to explain a proper formula and conditional format for your data.