T15 is correct. HP & Compaq got so much flack from techs about the T15 screws that they changed it to a modified Torx screw that can use a T-15 OR a flatblade screwdriver to remove them. My HP DX2200 mini-towers for one have the modified screws.
I used to change then to Phillips head screws but now I don't bother. If I can't find my T15 then I grab a flat tip.
I used to change then to Phillips head screws but now I don't bother. If I can't find my T15 then I grab a flat tip.