my brother recently purchased a brand new macbook right before christmas and it had to be exchanged due to a rubbing issue with the hinge and the fact that the harddrive would lose KB, MB, and sometimes GB of memory. Today the computer was returned and he was given a brand new macbook. This computer is fine except it still loses some space after using it just for internet and ichat. Right out of the box not even touched with other apps or anything. Anybody have any insight on to whats going on or if anything needs to be done to stop this from happening? or i it normal for macbooks?