Please provide more information.
What operating system are you using? Do you have all of the updates, including those that do not install automatically, as well as the latest version of Quicktime?
What model of camcorder is your video coming from and what format and resolution is it?
What are your Premiere Elements project settings (listed under the Edit menu)?
How fast is your processor, how much RAM do you have and how much free, clean, defragmented space is on your C drive?