>>i have a grid. the user can select either to fax or email to whoever is listed int eh grid. Now, how can i ahve the grid come up, adn based on whether or not the receipient has a email address or fax number, then that particular checkbox shoudl be disabled....dont' want to give the user the option to select to send a fax to someone and they dont' have a fax number...

iif(empty(whatever.faxdata),.t.,.f.) is exactly the same as
empty(whatever.faxdata) (empty function will return a .t. or .f.)

so put "!empty(whatever.faxdata)" in the columnx.controlsource of the column with the checkbox control.