Can you confirm that you are running PD9 v.2930 or is it an earlier version.
Your video clips are all .mp4 and your aspect ratio is 4:3, can you give us the clip properties - resolution etc.
You also have an itunes .mp4 in the library but the maybe not in the timeline?
Ideally you need to follow the appropriate parts of the guidelines here :
http://forum.cyberlink.com/forum/posts/list/7958.page
before we can do anything but guess.
A screen capture of your timeline is a good starting point.
Cheers
Adrian
Life is really simple, but we insist on making it complicated. (see below)
Confucius
AMD Phenom IIX6 1055T, win10, 5 internal drives, 7 usb drives, struggling power supply.