If you used relative paths for your video files, you can just change the common part of the folder name in the Preferences.
If you are using default absolute file names, it is still possible to change Local Path values in a batch. For example, your old folder for all the movie files was d:\ and now it is e:\movies\ follow the steps:
- save a backup copy of your database using menu item "Database - Backup"
- go to Preferences (menu item "Tools-Preferences") "Expert options" tab
- paste "d:\" without quotes to the common folder line (under "Use relative paths ..." option)
- turn on "Use relative paths..." option, the program asks to change existing paths, choose YES
- go to "Expert options" tab again and change d:\ to e:\movies\
Now the program should "see" your files again