Hi! If anybody could help me with this I'd be really, really grateful!

I am designing a new tracking document, and this will be used by several
people. In case anybody makes a mistake, I have entered a formula to one cell
so that if this particular mistake is made (leaving a cell blank within a
particular range of cells), the warning cell will shade red and the text will
pop up reading "Fatal Error". Hopefully the user will notice, but if they
didn't, they would currently still be able to save the worksheet with this
error present.

I am trying to find a way to disable the save option if this particular cell
does show the text "Fatal Error". They would also need to be informed that it
cannot save (otherwise they may think it HAS saved and lose all the data
inputted). It would be even better if it was possible to show a dialog box,
where I could choose the text shown, reminding them of what the exact error
is, so that they can rectify it and then save the file.

If there is a non-macro way that would be ideal, but if not I can try VBA. I
am very new to this but I'm pretty sure I could follow instructions on it.

The "warning cell" is cell BD1 on a sheet named "Individual Support". (Sheet
4)

Does anybody have any ideas? I'd really appreciate the help!
Neil