Do you really mean Adobe Premiere Elements 1? Could you have meant Adobe Premiere Elements 11?
Please confirm Adobe Premiere Elements version and tell us on what computer operating system it is running?
Lots of questions needing answers in order to sort through the details to resolve your issue.
Properties of the video that you are putting on the Timeline....video compression, audio compression, frame size, frame
rate, interlaced or progressive, file extension, pixel aspect ratio. Some times we can get at that information by you
telling us the brand/model/settings of the camera that recorded the video.
Next comes, what project preset (project settings) were set for the project? Do they match the properties of the video
that you imported into the project?
When you view the playback of the Timeline content in the Edit area monitor, have you Timeline rendered the Timeline content
to get the best possible preview? You say yes. Is there a green line over the content that is being played back in the Edit area
Let us start here and then decide what next based on your answers.
Please do not hesitate to ask if you have questions or need clarification on any of the above.