sorry to see your question is "not answered" because I have it too, now one day into using PE 12.
I have 7+ yrs experience with FCE on a MBP, bought Elements to use on a small-screen PC laptop so I could slap together just-shot clips for immediate sharing on dive boats et al. Neither single clips nor sequences on the timeline play like a movie should - a few seconds of fluidity and then grinding down to a frozen halt visually, though the audio plays on as if all is OK..
If you make any progress would you please post the details here?
Thanks,
Sharron S.