Hi all! I need help with programming a macro. Currently, I have a
macro which when I run it, grabs data from certain cells and copies
and pastes it in another worksheet. That is working well, so no
problems there. However, I need to add another element to this macro.

In cell B2, I have a drop down list containing 4 values: "C", "X",
"A", and "T". If the user selects "X", then (s)he must also fill in
cells E1, E2, and E3 with pertinent info. If the macro is run, and
those cells are blank (given that B2 is "X"), I want an error message
to pop up saying "Can't export data unless cells E1, E2, and E3 are
filled in."
This would essentially halt the macro and the user has to fill in the
data, and re-run again. If any other value (other than "X") is chosen
in cell B2, the macro runs successfully.

Can anyone please help?

Thank you all in advance!