Checkbox will not uncheck

I have the following checkbox code:

if  (this.rawValue == 0)

{

     hc1.value.integer.value=0;

     hc2.value.integer.value=0;

     hc3.value.integer.value=0;

     hcgray.presence = "hidden";

     sfrhc1,value.integer.value=1;

     sfrhc2.value.integer.value=1;

     sfrhc3.value.integer.value=1;

     sfrhcgray.presence = "visible";

}

else

{

     hc1.value.integer.value=1; 

     hc2.value.integer.value=1;

     hc3.value.integer.value=1;

     hcgray.presence = "visible";

     sfrhc1,value.integer.value=0;

     sfrhc2.value.integer.value=0;

     sfrhc3.value.integer.value=0;

     sfrhcgray.presence = "hidden"

}

The problem I'm having is (1) For the hcgray to be hidden I have to select hidden in the object pallet and (2) I can only check the box I cannot uncheck it.