Stuck in bios mode

i had Lubuntu 16.10 in my laptot, an Asus. When i tried to install the Ubuntu Mate 16.10 i had a problem when i was particionating the disk. After that, i had to reiniciate and i am stock in the bios mode. The onl boot option i have is from my usb but i dont hace the option to install it.
How can i solve it?

Boot into live session and install from there.

Already done. It didnt work

Disable secure boot in bios/UEFI for legacy boot, then try to install from a live session.

Let’s clarify a point here.
Are you stuck in the BIOS, or can you actually boot the LIVE USB when you select this boot option?
Meaning, do you get to see the Grub menu or the Ubuntu MATE Splash screen?