I'm owning a macbook pro 13 inch mid 2009 and a USB thumb drive Kingston DataTraveler 100G3 16 GB.
I successfully installed Windows 7 on my Mac using Bootcamp ( with a little trick to enable "Creat a bootable flash drive" feature which was hidden in my bootcamp version ).
The problem is, after about 1 month, I followed exactly the same procedure, with the same USB and ISO installation file on my friend's computer ( Macbook Early 2008 model ), it just didn't work. When I tried to boot into USB, it said : "No bootable device - insert boot disk and press any key ". Similar to this video : https://www.youtube.com/watch?v=NgWBY6IezQA
And to be even more frustrating, I tested it on my computer again to check whether there was something wrong with my friend's computer, my computer couldn't even boot into the USB again
I'm really desperate now. I feel like there is some mysterious thing going around here. My USB's working perfectly otherwise.