Yesterday I changed the RAM of my Macbook Pro 13" (AB990SM/A) I successfully expanded it from 2 to 8GB, everything works fine so far. However after closing the MBP, there was a small piece of cardboard left on my table. I made a photo of it: http://i52.tinypic.com/2d15tf6.jpg So I opened it again and tried to find where this piece belongs to. After searching about an hour plus searching the internet up and down for another hour I could not find any useful or logical information about this piece. I ended up closing the MBP and start to work without the piece, but I'm worried. Perhaps some of you have experience with this?