Those clips on the front edge are very challenging. I have a set of nylon pry tools that are for taking apart car dashboards without scratching the vinyl or plastic. I was able to get a long one in from the side and twist it which freed the clips without damaging the plastic on the upper case or the aluminum on the lower case.
Putting it back together presented another challenge. When I first re-assembled it I think I pushed too hard over the DVD slot and accidentally bent the metal down. I was able to bend it back up using a thicker part of those same nylon pry tools, and then i was able to get it snapped back down successfully. Had I known this would happen, I would have just put the nylon tool in the slot to reinforce the metal as I was snapping the case back down.