I want to fire my macro when cell "b3' has the value of "#N/A". I have tested
my macro and it runs fine with b3 = #N/A; but I can only get it to run if I
run the macro manually. I want it to run whenever b3 = #N/A. The macro
performs to change the value of b3 to a non-error value.

How can I get the macro to fire when b3 = "#N/A"?

Thanks for your help.