I've created flash drives and DVDs with what should be bootable Spinrite images, but none of them show in the boot list on my DELL. I even tried a flash drive with just FreeDos and nothing. Flash drives with linux installs and the MS Windows Media Creation tool all show up in the boot list and work fine. What is it about an image with FreeDos that keeps it from showing itself. (DELL Inspiron 3020 S with BIOS 1.12.0)
