Vista - hardware acceleration

i get to the "change settings" button and it's not hilited and clking it does nothing..

before i do this,,

Administrator Account

after a log off and pick the new Administrator account and log on,,, will the "change settings" button be hilited then and active????

i need to turn down hardware acceleration for some of my programs to work..

if this isn't right,, could some one lead me in the right direction..

thanks