These things can be caused by any of a number of things.
How fast is your processor and how much RAM do you have? What operating system are you using? If you're using a Windows operating system, have you gone to Windws Update manually to ensure you have even the non-critical updates?
Have you gone to the ATI or nVidea web sites and ensured you have the latest firmware for your graphics card? Have you gone to Apple.com and ensured you have the latest version of Quicktime?
How much clean, defragmented space is on your C drive?
What type of camcorder is your video coming from and how did you get it into your computer? Which project settings did you use when you started your Premiere Elements project?
There are also other possibilities too -- which is why it's very hard to troubleshoot such a general problem on a forum like this.
I would start with this ARTICLE, and work through the material in the upper portion.
Then, look at the various links, that it contains, as there are many other articles on setting up one's computer for video editing, including memory and resource issues.
If nothing in that article, or its links, helps, see this ARTICLE for the additional info that would be so useful. Steve has begun the Q & A part of the troubleshooting.
Could you please let us know what is it that you are trying to do? At what stage(s) does it crash?