I have an Alienware Alpha and disabled Secure boot in the past because I wanted to try and install Linux. Just recently I decided to install Windows 10 back on my system. I have a few questions, does secure boot only protect you from external or "physical"  attacks, or can they also protect you from internal attacks such as an application you installed in Windows? Due to me disabling Secure boot, installing Linux and not turning it back on for a long time, is my Manufactures Platform Key still in my BIOS so I can turn it back on? Lastly when or how should I turn secure boot back on? Can I turn it back on after doing a fresh install of Windows and installing a bunch of apps, or should I turn it on just after doing a fresh install of Windows without installing any apps? Thanks!