To play Blu Ray on Media Centre PC, does the motherboard have to be HDCP compliant as well as the video card?

well to play Blu Ray you need an HDCP ready graphics card which im uming your 3450 is, if not there are 8500/8600 nvidia cards that are, a HDCP ready monitor which can be costly, a Blu Ray player, and software that can play Blu Ray video's like PowerDVD 8 Ultra or WinDVD 9 Plus, so your motherboard as long as it has a blu ray drive installed and has a HDCP video card with an HDCP monitor, will be able to play Blu Ray