I have a project that requires a cell to change with different variables.
The cell can either be blank, use a number from a vlookup that is lower than
listed in the vlookup at which time the text message "customer n. than...
appears, or the number is in the vlookup range, or the number is greater than
the numbers in the vlookup and enters an "NA" result at which I used the ISNA
function which then in turn leaves the cell blank. The cell needs to have
the text "customer n. invalid" in the cell. The following is the formula I
have so far and the only thing it does not do is enter the text "customer n.
invalid" when the result is false.

=IF(E8="","",IF(E8<customers!$A$3,"Customer number must be greater than
"&customers!$A$3,IF(VLOOKUP(E8,customers!A3:A11,1) ,"",IF(ISNA(VLOOKUP(E8,customers!A3:A11,1,FALSE)), "Customer
number is invalid",VLOOKUP(E8,customers!A1:A3,1,FALSE)))))

I would appreciate any help with this. I have spent many hours trying to
make this work. My whole project is full of these type of excel formulas.
--
Minnie