I meant F12, not F11 in my last post, sorry. So yeah, you want to go into BIOS (F2) and look around in the submenus for references to boot sequence and a list of hard drives. When your USB drive is plugged in when you turn on the PC, it should be detected as a hard drive. What you want to do since it's not showing up on your F12 list is set the flash drive as your primary hard drive (place it as first on the list). That way, when you select boot from hard drive, it will try to boot from the usb drive since it is listed as your primary hard drive. Keep in mind that you may not be able to boot from a USB drive at all on this PC since it is an older model. This is what I have done on some older models and have been successful. Good luck...