I recently purchased a 1 GB stick of memory, DDR2-667 (manufactured by PNY) and I can't get it to fit inside the slot. I checked an re checked various sources and this appears to be compatible with my macbook. I've tried "firm" pressure but I'm almost positive if I used anymore force I'd break something. Upon further inspection, I noticed that the memory module is thicker than the stock memory module that came with my Black macbook. I don't have a tech background so the best way I can describe is that the unit has "black square things" on both sides whereas the modules already in place only have them on one side. Yea, I don't know the correct terminology. In any event, is this normal? Thanks for the help!