This formula, with a Data Validation type of List is not quite what you
asked, but will only allow Yes if A1 is Yes, No if B1 is No, or else gives a
list of what is in G1:G2

=IF(A1="Yes","Yes",IF(B1="No","No",G1:G2))

pre-load G1:G2 with Yes, No

--
HTH

Bob Phillips

(there's no email, no snail mail, but somewhere should be gmail in my addy)

"franko" wrote in message
...
can anyone help....

I want to use data validation to allow a drop down list in a cell but only
if certain criteria are met.

e.g. If A1="yes" then show yes in the validation cell, if b1="no" then
show
no, if not then shown the dropdown list for yes/no

At the moment i have the validation in cell d1 as a list with this
formula:
=IF(OR(A1="",B1=""),YESNO,IF(A1="YES","YES",IF(B1= "NO","NO",YESNO))))

With the name of my list being yesno

thanks for any help