Problem Regarding Standby

Hey guys, i would like to be able to use standby on my comp, but can't seem to be able to use it because i cannot press the button(not allowed 4 some reason). IS there any way i can use standby on my comp? I use Windows XP SP2. If u need any more details plz feel free to ask, i am more than willing to give it to u, so that my comp will work properly. Thanks guys.