My notebook is the ASUS N56VZ 4066. This has been updated with the latest American Megatrends BIOS and doesn't have Secure Boot BIOS settings.
When purchased, this came with Windows 7 on a mechanical disk, which I replaced with an SSD - It also came with a £15 Windows 8 upgrade offer from Microsoft which I took up and upgraded the OS - after changing a few drivers all was OK.
After upgrading to 8.1 however I now have the 'Secure Boot is not configured correctly' watermark over the desktop.
This will NOT be remedied by changing BIOS settings - C'mon Microsoft and fix your problem !
Alternatively, the watermark can be made to go away by disabling UAC, but then no Store access - I'm thinking now that this is preferable to having the watermark...