Hi SimonJia, This system is designed in such a way that it does not have an option to boot from USB. Please reply for any further questions.
Hey guys, I got a new Inspiron 15R 5520. The problem is I can't boot the laptop from a USB stick like I did on N5040(My 2 years old laptop), and there is no option to do this. First, I hit 'F2' to enter the BIOS setup page, there are only 3 options under the boot device: Hard Drive, CD/DVD, Network. I restart the computer and hit 'F12' to select boot device, still no USB. Does Dell freeze the function to boot from USB device? Is there any solution? Thanks in advance.  
Boot from USB device on Inspiron 5520