Firstly thank you for reading my post and for the answer.....
I have those options, but i also have an option to choose from whether to boot USB as
Boot USB in Zip Emulation
You see there are so many extra combinations and permutations that can confuse.
Basically a new problem that i am facing is that i have a 1TB WD (My Passport) external hardisk, which i wanted to use as a boot device. I wanted to make it into a USB (like a pendrive where you can install bootable iso cd's from the portable HDD, i have done it for a usb pendrive), but have not been able to do it for this 1TB external HDD. It just doesnt recognise (boot) from the 1TB external HDD, and so i was wondering what settings do i have to adjust in the BIOS for the 1TB external HDD to be recognised in the same way that the usb pendrive is recognised.... the pendrive is only 8GB so no problem, but i think there might be something that i have to do in the BIOS settings of the USB options for the 1TB external HDD to be regonised.