Hi Karen,
Ok, I don't know the configuration of your system and I'm not a techie. The general advice on this sort of situation is to carry out a looksee over your system, reinstall some software and the re-install/locate any new drivers. You also have to be aware of updates (background updating) that can affect your system.
http://forum.cyberlink.com/forum/posts/list/2405.page
Subject: PowerDirector - information we request and tasks to carry out.
Part A, check and update
Part C, carry out
Part D, yep, read this one.
Part E, F, G - they'll help
Part P and Q (Q in case you've used a divX in your project)
Part S - this deals with gathering "crash" information.
Please update your graphic card driver, Defragment your hard drives, edit from an internal hard drive NOT usb.
General info:
PD7 - image/tip guide resource for video editors
http://forum.cyberlink.com/forum/posts/list/3522.page
PD7 - VIDEO guide resource for video editors
http://forum.cyberlink.com/forum/posts/list/3523.page
Sorry not to be precise and resolve this for you immediately. I've given some general things you MUST do. If the issue persists please post again.
Dafydd