Did you download an ISO or the files? If files, use Jon's link given above to make them into an ISO.
If ISO, I use Imgburn as it never fails. Select Burn Image to Disk, Load the ISO in using file folder icon, make sure it says Bootable in the text given, put a DVD in the drive and burn at 4x speed with Verify.
Just loading the ISO into ImgBurn now will tell you in the text if it is bootable: Attachment 41128