Booting from the USB drive (Dell Inspiron N5010)


Hey, I'm working on triple booting my PC with Windows 7 (already on it), OSX Mountain Lion, and Ubuntu. windows will be the primary OS, and I've set aside unallocated space to partition with both OS X and Ubuntu. however, I'm having a bit of trouble booting from the USB drive created from Unibeast. i got OS X and put it on the USB drive using UniBeast with added laptop support, and when I boot my PC up, it shows up and lists 3 different options; the first just says 1,1. the other 2 are my pre-existing windows (main OS and recovery). I'm not finding anywhere to select the USB device. all devices are unplugged and nothing is in the optical drive. So, I rebooted. this time that first screen (unibeast) doesnt quite show up and this show's up instead: Booting from the USB drive (Dell Inspiron N5010)-imag0004.jpg (the selected line says "hd(1,3) OS". When I select the first one (that doesn't have windows) and push enter, it says "No Loader".

do I need to recreate the USB boot drive?

oh and in case you're wondering, here are the PC specs:
Dell Inspiron N5010
Intel Core i3 CPU M 350 2.27GHz quad core
4GB RAM
Intel HD Graphics ("video card")
DW1501 Wireless-N WLAN Half-Mini Card (wireless adapter)
500GB HDD with windows 7 installed, 86.67GB unallocated space for both Mountain Lion and Ubuntu

help? and thanks!