This is what you will need for Blu Ray:
http://www.nvidia.com/object/pvhd_system_requirements.html
Here is the review for your computer: http://www.comptalks.com/forum/laptop-reviews/packard-bell-easynote-lm-review/
From this, it appears that the video (graphics) card is inadequate and you may experience difficulty in replacing the existing DVD drive with a blu ray drive. The on-board (integrated) graphics may not be adequate.