Hi everyone

I'm not new to Linux, but new to creating a bootable USB thumbdrive. Now, I've tried the Unetbootin-method twice and I've checked the MD5, and everything went smoothly.
But my computer won't boot from the USB stick. First of all, there are 4 types of USB to boot from:
USB-FDD (i assume: Floppy Disk Drive)
USB-ZIP (no idea)
USB-CD (the whole CD architecture is on the USB stick?)
USB-HDD (Hard Disk Drive)

Now, first of all: Does Unetbootin write a boot sector on my pendrive?
Which of those USB-types shall I choose to boot? Until now none of them has worked.

Specs: Windows 7 Ultimate, 64bit
Apacer 8GB flash drive

How do I get this to work?

Thanks for your patience and explanations!