When I disable this in the BIOS, Task Manager says I don't have virtualization, but SecurAble and PIU say I do! (VirtualBox still says NO YUO). WTF is going on, here? Am I missing something obvious?

If Virtualization keeps turning off when your system reboots, you need first to check if VT-d, or VT-x is enabled on your BIOS. If they are not enabled, do it and then turn on Virtualization. If ...

If you're fond of trying out multiple operating systems without the hassle, you're probably using virtualization regularly.