Alternative way to verify ur files haven't been moved when using WINDOWS MOVIE MAKER
u said u checked...so i suppose this is kinda repetative...but when ur in movie maker if u right click the media listed in the imported items section, then click properties, it should list the name, file type, resolution...if it doesn't then ur file has been moved. perhaps the file is gonna be too big...the new windows media player saves in much higherquality than the old versions...maybe try saving to a cd. Also if u right click the file u can go browse file location and it should list ur file under that location.