Did you consider offering a little more detail? Maybe even a lot more detail?
Bill is right. Even Sherlock Holmes needed a few clues.
You can start with which version of the program you're using on what operating system.
Also, what model of camcorder is your video coming from and what format and resolution is the video?
Finally, look under the Edit menu in Premiere Elements and post the Project Settings for your project.
its on premier elelments11 its an mts format on windows 8 never happened before
Let us know when you'd like to provide us the details we're asking for so we can help you troubleshoot this issue.