Title pretty much speaks for itself. I've always had SecureBoot on, and have never had a problem with this machine. And all of a sudden a few days ago, with no hardware changes whatsoever, I suddenly can't boot from any other media device unless SecureBoot is off. Be it DVD, ISO image on USB, nothing. An already installed Windows will load just fine with it on, just can't boot from any other device unless I turn it off first. I'm just really confused as to why this is all of a sudden a problem when it never has been before. Anyone have any ideas?