you must have a rough idea where in the country she is likely to be registered, and do you not know when her birthday was? if you do it will narrow your search to various quarters, Q1 is jan to match Q2 april to june Q3 july to sept Q4 oct to dec. Is there not an age on her gravestone or death certificate? can u not find her death registration which should show her birth registration if she died after 1974 (think it changed then). you don't need a birth date to order a certificate, if you find a number of likely birth registrations for her, send off the fee, list the possibilities but add the info on who you need her father to be based on the info you have from the certificate of marriage. the person dealing with your order will only send you the correct one based on your info. negative research is almost as valuable as positive, as you at least know that you have eliminated certain possibilities and so your search narrows.