[ubuntu] Can't boot Ubuntu iso from USB stick

view story

http://ubuntuforums.org – I am trying to boot an Ubuntu iso from an USB stick. My BIOS is from American Megatrends (1985-2005). There are three boot devices mentioned: 1=CD/DVD, 2=hard drive, 3=realtek boot agent. At each number I can use one of these 3 options or disabled. No other options are mentioned. Also mentioned is Boot from other device, this is set to yes, the other option is no. How can I boot from USB? (Hardware)