I deleted Win 8 but but only by running DBAN for some 30 hours (about 29 unattended) to do the deed. FDisk-like functionality in other OSes wasn't good enough and neither was rendering Win incapable of booting by rearranging folders, since that meant I couldn't boot Win but also that I couldn't install another OS, restore Win from a partition, or remove the Recovery partition. I could boot and run from a live disc. I should have tried loading the live-disc OS into RAM and running the infamous Linux command "rm *.*" (warning: don't do it unless you realy mean it, since it operates without confirming) but didn't think to run it. I don't remember if I tried using the live-disc OS to read the hard drive and let me rearrange folders back to their original arrangement.
But: The machine says "Booting in insecure mode". I thought I was okay about making DBAN delete Win8 until I Googled that phrase and found http://lwn.net/Articles/500231/
(plenty more good articles and posts seem to be online) and wonder if next time I have to get only a computer that is Linux/*BSD-compatible. I also wonder what the insecurity is risking; I now use the computer to access the Internet without using a live disc, and I don't care to get cracked or my system pumped with malware. I also wonder if an intranet would be a security problem because of this. The thought of having to secure my machine against BIOS updates from remote sources is unpleasant; bad software updates can be cured with a reinstallation of software but I guess the cheapest cure for a bad hardware update is to buy another machine. I understand ChromeOS machines are okay on this but, according to stores selling them, they apparently don't allow local file storage, forcing reliance on a cloud and abandonment of my flash-based files. I need to be able to secure a computer that can run Windows or OSS. Are my security concerns misplaced?