My 13" Macbook Pro has been acting up for a month or two now. It has episodes of being really slow, getting the rainbow spinning circle with everything, throwing me out of apps and can't even play a song on iTunes without freezing. (at worst, I counted it stopping the song 16 times in 3 minutes - then one time it froze for as long as 3 minutes). I have tried everything I can think of, I have plenty memory (I only store music and photos on this computer), I have even reinstalled OS X and verified and repaired disks. It even froze two seconds into startup as I was putting my password for my account to open the desktop.