Go to "Advanced BIOS features"
Go to the "1st Boot device" and set to "USB disk" or "USB HDD" or sometimes may "USB-Stick" or "USB memory stick" or "USB-ZIP"
What bakunin is trying to explain is that OS like DOS are understood as an OS where all know on what/how it runs, same goes for Windows... UNIX, since you talk about flavors cannot be compared in the...