I'm stepping away but I had a similar Asus and had to google the bios key to hold down prior to power up.
I have an Asus x55a with windows 8. I'm not the admin and cant get their password. I am trying to boot form usb to install Lenux. However there is a windows error, 80070490, that i cant fix unless I'm admin. I cant set to factory setting until i fix this error. I cant see the UEFI selection from settings as a guest. And I cant figure out how to find the boot menu. I have looked at everything. Please help. I can post pics of my screen and what im seeing if it helps.