kangaroo install

Hi I tried to instal kangaroo B 0.0080 into grasshopper 0.8.0003 in rhino 4 sr8, on a pc running windows xp pro 2002, sp2 but it won't show. I have copied and pasted both the GH and dll files into the special folder>components folder - when I right click properties on both files i do not see a security tab where I can toggle 'unblock' - any ideas ?