If I'm Using Nero To Burn Movies, How Do I Free Up Disk Space To Allow Me To Burn Dvd?

Are you using an empty disk? OR Is your disk is re-writable? These things need to be considered. Some disk are writable, that means you can only write once and cannot delete anything from it. They are cheap in price usually. Other ones are re-writable, which you can use again and again to write and delete the data. Notice, you can't delete merely by using windows. You will have to use nero burner to delete any files from  the DVD. There is an option in nero burner to delte the data files. Have a look at it.