Empty security header after ubuntu 12.10 gnome 64bit
 

Hi all,
I have problems in dual booting ubuntu with windows 8 since two months.
I've tried to install win 8 from cd but the system refuse to install. It claims for misterious drivers for my hard drive. I've nevere heard something so. So I've tried another way.
I've tried to install 12.10 with gnome desktop without disable secure boot. Actually ubuntu has been installed but I've lost Windows 8. Only ubuntu now works.
Moreover my headache is worsen by another problem. At reboot, my DELL xps 8500 warns me as follows:"empty security header".
What does it mean that warning? And also, how to recover the security header?
By searching linuxquestions I've not found similar issues.
Please help.

dvchp