If your version of PD7 crashes all the time, there are some thing you can do to help...
1. If you are running Vista: Turn off 'Super Fetch'. (this might help, usually it makes it a little faster)
2. Check the file size that you are trying to edit: If you are using .avi they are usually quite big, try downloading a batch video converter like 'Any Video Converter' from here: http://www.download.com/Any-Video-Converter/3000-2194_4-10661456.html Try converting your videos to .WMV or .MPG they are much smaller and the quality does NOT go down. This makes PD7 much quicker and so far I have had no crashes since I changed the file type.
3. If you have the error message "No More Memory":Try uninstalling PD7, defragmenting the hard drive and re-installing PD7. Or you can change the Virtual Memory in Control Panel this may also help.

All of these should help you if you have any other solutions please post them bellow this one.

TMcC Media

P.S. This is a video I have made with PowerDirector 7: http://www.youtube.com/watch?v=UGXhBPDETmY&feature=channel_page