What version of Premiere Elements are you using and on what computer system is it running.
Based on recent posts here, you probably are working with wmv video.
If so, please read the Announcement at the top of this forum which targets the 1/2 wmv display related to a recent Windows Update kb.
Besides the Announcement at the top of this forum, there are many, many threads here on the topic.
Please let us know if you found the Announcement and deleted the Windows Update causing the problem.