I'm running a Dell Inspiron 3520. I decided to install Ubuntu on this alongside Windows 8, because I need it. I downloaded the amd64 iso since my laptop is 64 bit. I put it on my usb using UNetBootin. I turned off secure boot. After it boots, I get a Grub command prompt. Why doesn't it show the boot menu? I'm sure it installed correctly. I tried installing it twice, but I still get the same results. What's the problem? By the way, I get the boot menu when I'm trying to install it using the live usb. I looked at other questions but they got it when they upgraded.