I'm with John. We need much more information.
What operating system are you using? Have you ensured you have the latest version of Quicktime, per the program's requirements? Have you manually gone to the ATI or nVidia web sites to ensure you have the latest driver for your video card?
What model of camcorder is your video coming from and what format and resolution is it?
What are your project settings, listed under the Edit menu?
I will try and do my best to tell you what I am working with. I am only doing jpegs for a picture video for a wedding. No vamcorder is available. I have the latest quicktime per the requirements of Premiere elements 11 I used to work on an apple computer and now I am doing this on a PC. This is what my screen looks like.
Have you resized all of your JPEGs to no larger than 2000x1500 pixels?
Have you manually gone to Windows Update and downloaded the non-critical updates, which do not download automatically? And have you gone to the ATI or nVidia web sites to ensure you have the latest drivers for your video card?