WIndows Vista administrator problem

I setup an administrator password. when i went to download a program, the administrator password box came up and I entered the password. Didn't work. i tried every variation of the password that I could think of and nothing has worked. I even tried to use a password recovery program, but, how can I download a program to get my password when I need the password to download the program?! So, what can I possible do to unable/ turn off the administrator?