Hi Richard, Try googling death certificates and the county name. Then see if there is a form to print and complete to send in with payment or an email address to ask someone how to obtain the certificate. I found this for Oswego http://www.oswegony.org/DEPT_clerk.html
I haven't yet gotten any certificates from upstate NY because my family mainly lived there before certificates began but I have obtained certificates from NYC and various counties in Illinois. Don't go through Vital Check and be sure to ask for genealogical certificates as these are less expensive. Good luck!