got a real basic question to ask and you're gonna think im an idiot for asking...I just bought a 320gb western digital elements hard drive and want to reformat it so that its compatible for both mac and pc's. i intend to format it as NTFS-3G as it would allow me to use it on the 2 platforms without having the 4GB file size restriction that fat32 has, anyway..... when I go to reformat my external hard drive in disk utility, I see my external hard drive to the left, and there's a "sub" hard drive as a child of the external hd listed uppermost. just wandering which one of the two do i select before going to Erase>Windows NT filesystem (NTFS-3G)>erase? Do I select the uppermost drive and erase that or the lower one? or both? just want to be absolutely sure as Ive had bad experiences with hard drives before. thanks in advance!