Ubuntu installation from USB doesn't work.

[JamesBwoii]

Yesterday I installed Ubunutu from a USB, but not the latest version and I accidentally downloaded 32bit instead on 64bit. Today I downloaded the latest build of Ubuntu in 64bit, created a bootable USB, changed my BIOS to boot from USB, but whenever I start the computer up it just loads Ubuntu straight from the HDD. Why is this happening?

Thanks.

[mzrk7]

What is your hardware? As a precautionary measure I would try to make another bootable usb.

[spideryada]

Make sure that your flash drive is plugged directly into an USB port and not a hub.