One thing to note, you can't force a user to either leave a cell empty or
enter something. There are little things you can do to try to coax them to
follow those rules but in the end the user has all the power. ( the ON/OFF
switch!)

So, try this:

Select cell B1
Goto the menu DataValidation
AllowCustom
Formula:

=AND(COUNT(A1),A10,OR(B1="N",B1="E"))

Uncheck the "Ignore blank" checkbox.
If you want custom messages to appear select the Input Message and/or Error
Alert tabs and fill in the info.
OK out

--
Biff
Microsoft Excel MVP


"Dearoledad" wrote in message
...
How do I set up validation of data entry in cell B1 depending on the value
entered in cell A1? Valid entries for B1 are - blank if A1 < 1 or N or E
if
column A1 zero.