I have a worksheet that I want to ensure users complete certain cells and only when all the specified cells have been completed a message in another cells says "Complete". prior to that it says "Incomplete".
The way I have found thus far is to use the ISBLANK function but 2007 will not let me add any more cells to the formula. I've tried the syntax ISBLANK(A1:A50) but it is not recognising the range.

Is there a better way to do this or is there away to use a range with the IS function?