I zero'd out my hard drive with something called kill disk. It unfortunately doesn't have a format option. So now my hard drive is basically 20GB of unallocated space. When I boot from my USB (which has kill disk on it) and then I exit kill disk, I see a DOS prompt.
This is FreeDOS, and has a limited set of executables. However, I can load executables onto my USB and then they will be available for me to use on the freedos prompt.
Question: What executable(s) should I put on this USB so that I can run them and eventually format my hard drive so it is usable again?