|A USB KEY being a flash drive? |
You'll need a viewer that's compatible with whatever the file types are that are on the drive. Have you tried clicking on one of the video files? If windows 7 already has a utility to view it, the file should open.
If not you might try something like VLC. If you still have problems post back the file extensions of the video files. There's some info on VLC and file extenstions in my reply here: