Custom profile fields are are in the userfield table, to alter those its something like
PHP Code:
UPDATE`userfield`SET`fieldX`='No' WHERE`fieldX` =Yes;
so change fieldX to your field number like field10. Dont forget to change the userfield for how it is in your database, if you used a prefix "vb_" then it would be vb_userfield, if you used a prefix say "xy" then it would look like this xyuserfield.