I'm trying to install Ubuntu 12.10 on a Lenovo Ideapad S300. It has a special power button on the side in order to get to the boot menu. I've created bootable USB sticks with various programs (e.g. unetbootin). All of them fail the same way. When the computer is turned on (using either of the power buttons) the Lenovo (BIOS) logo is displayed then the computer turns off and on and off and on and...

Pls help I'm stuck with Windows 8 and it's embarrassing and super scary!!