My DVD-Rom recently broke and I have installed Ubuntu from my USB stick with no problem. But now when I enter BIOS, there is no Option for USB. I hit F8 and it's not listed there either. I know my BIOS supports booting from USB because I used it before but I don't know what happened to it now. Please help, thanks.
Please review this article with the guide how to enable USB support in the boot time.
I think you have it disabled since you are using PS2 keyboard. Its under