I just bought a DVD-R and I want to burn a movie onto it but my computer isn't recognizing that anything is even in drive F (DVD Drive). Why is this so? How can I fix this problem? Also, I have the file as a .m4v but it keeps on thinking that it's an audio file and that it has to be burned to a CD-R. How do I put it into a format where it will go in as DVD-R?