Try this:

=LEN($G$51)

Uncheck Ignore blank

--
Biff
Microsoft Excel MVP


"RayportingMonkey" wrote in
message ...
I am trying to use a custom data validation formula to prevent entry in a
cell if another cell is blank.

If I enter:
=ISBLANK($G$51)
I get the opposite of what I want... Cell G51 is blank and I do not want
the
user to be able to enter data in the cell I am using validation on.

If I enter:
=(NOT(ISBLANK($G$51))
The user can enter data into the cell I am using validation on regardless
of
if there is data in it or not!

I am using Excel 2003 SP3.

Not sure what's up with this and couldn't find a similar post... I
appreciate any insight!

Later-
Ray