If the files are mp4, look in other media, you'll need to reencode them if you want to see them in video library. Also, try this: right click "videos" in wmp, manage video library, add your video folder. Video folder will remain in its original location, but the content will be shown in the library. Can't think of anything else right now, to tired, going to sleep. Will finish as whs above, hope this helps.
cheers