can't reset administrator password

I need to reset my administrator password so that I can install updates and programs on to my computer. I can not for the life of me remember the password. I read here that if I tried 3 times with a wrong password it would prompt me to "reset the password". It has not done that and I tried 15 or more password combinations. Unfortunately when I set up my computer originally I apparently opted not to allow it to reset passwords using my appleID as well. Does someone know any other way to reset my password?

Thanks!