Start
Run
Enter 'cmd /k' (no quotes)
Enter 'cd\' (will get you the C:\ prompt)
Enter 'cd\(path) where path is the path to the folder where the stubborn mpeg's are, eg, C:\BadPictures
Enter 'dir /w'
If you can see the item, Enter 'erase [filename]'
If you had a folder to delete, you would use 'rmdir [folder name]'