new laptop will not start from USB flash drive

[Joep L. Blom]

Hi,
I have a new Asus laptop with Windows 8 pre-installed and an UEFI BIOS.
I made a bootable USB-stick using Unetbootin with Ubuntu Studio 12.04 (I 
only use LTS distributions).
When I put the stick in the machine and restart I see the start menu for 
choosing to try it or to install it.
I choose try (demo version) and then the system freezes nothing is seen. 
The monitor is blank, the various leds on the frontpanel do nothing and 
the only option is to remove the USB-stick and restart Windows8.
Can somebody show me how this can be solved? I assume it's the UEFI 
BIOS, primed to work for MS$ only but I thought that this problem had 
been solved.
Thanks in advance,
Joep