With the new PC in hand and all my files transfered over to it, it was time to wipe the hard drive so I can pass it along to a co-worker.* I use a program called KillDisk to over writes everything on a drive with zeros, then re-install the operating system, so that the next person starts with a clean slate.
*I was going to donate it to Goodwill, but found someone here at work who is starting a Tax Prep business and needed to keep that stuff separate from the household PC.
I made a bootable USB drive to erase the hard drives, but for some reason the PC wouldn’t start up using it. So I installed the Windows version and it wiped the secondary hard drive and it wiped the second partition on the main drive, but would not commit suicide by wiping the drive it was installed on. Not unexpected, the computer was just obeying the 3rd Law of Robotics: A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
I ended up burning a CD to kill the main drive.