well a month or so ago i bought a MBP, this ended up having a dead pixel so i swapped it out. I got a replacement on the spot. Ever since getting this one ive been having problems with the computer sometimes not waking up after sleep and just staying in sleep until i hold function. It also has recently started to have a slow tracking mouse cursor. I havent changed anything with the preferences it just al of a sudden starts to stutter and track slowly. What are the possibilities that can be causing this?