Install ubuntu 12.04 – Ask Ubuntu

The installation interface can not appear when I install ubuntu 12.04LTS on

my computer (CPU: i7 8700); it was installed correctly in my other
computer (cpu: i5 4590) using the same USB memory, it will also be a success when
install ubuntu 14.04LTS on my first gate.
Can you tell me why and how can I install Ubuntu 12.04LTS in my first
thank you