Copying a bootable USB to a DVD

greatgeezer

For various reasons, I need to install Win in a Virtual Box. Someone I know had a Win install thing on a pendrive. I simply dd'd this to my Linux hard drive - however the pendrive was SIXTEEN gigs, not 4! So, the file now on my HD is 16 gigs! I would like to burn a Win install disc to a DVD from that file - how do I "chop it up" so that ONLY Win is on it AND it's size becomes < 4.7 gigs? I guess I do that "mount loopback" thing, right? THEN what? How?

Thanks.