replacing windows 7 with ubuntu

I have created a bootable usb with UUI on windows 7 for ubuntu. Then I have plugged it into my netbook restarted and made the priority boot in the bios the removable device. Nothing happens. I also tried booting it in my mac.. Nothing happens. What can I do I have tried everything now and giving up :(

When I plug the men stick in my mac it is titled UUI.

But doesn't get recognised by either machine....