Well I don't want to just erase free space, I wanted to erase the whole disk. Nothing really sensitive on it, just doing an RMA for a Samsung drive making clicking sounds (calibration errors I've heard). I just used the Disk Management snap-in to do a full format, then opened the disk with HxD (freeware) and zeroed out the remaing sectors manually. Thing is I didn't want to use HxD to do the whole disk since it would be a copy/paste nightmare. http://mh-nexus.de/en/hxd/