Windows media center finds files that do not exist

When i open my windows media center under the movie tab i find files that are strings of numbers, and they are old vidoes that ive deleted. I can find them anywhere and playback fully? It doesnt make sense, ive tried searching for them and nothing comes up. these are full 20 minute videos that play on media center but dont exist on my computer.

Windows 7 64bit computer home premium

Thanx