Trouble installing Ubuntu with live USB

and sorry for bothering you,

I have just bought an MSI PE60. I have installed Windows 10 in Legacy boot mode, so I have to install Ubuntu in Legacy mode, too.

I want to install Ubuntu with the Live USB. So far, I have tried with the 15.10 version and the 16.04 beta version, but the problem is always the same.

I have taken a look at earlier questions, and it seems to be a mixtures of two problems:

When I boot from USB, the following message appears:

"Missing parameter in configuration file. Keyword: path gfxboot.c32 not a COM32R image"

After that, I write play, play-install or help, or whatever. Then it prints very quickly

"ACPI : EC: Fail in evaluating the _REG object of EC device. Broken bios is suspected"

and it does continue until the Ubuntu loading screen, where it does freeze.

I have disabled the FastBoot mode. There is not Secure mode, as I am booting in Legacy mode.

I caot use "nomodeset idle=nomwait", or disable ACPI (I think, as there is no grub, and as it loads almost directly the Ubuntu loading screen).

What should I do? :/

Thank you very much.