I'm trying to install Ubuntu 14.10 x64 on my laptop. But I always get "booting in insecure mode" message and then nothing happens. My laptop has BIOS Legacy not UEFI. There's any option about security on BIOS beside BIOS password. My laptop had Ubuntu 14.04 x64 and Windows 8.1 x64 installed, so I wanted upgrade Ubuntu to 14.10 performing a clean installation.
So, how do I solve this error?