dose your machine support booting from USB?
is usb memory in your boot order in the bios?
most older machines dont support booting from usb.
some older machines do but only support 128/256 Mb drives
you need at least a 2 gig usb key
go here follow this tutorial it works from windows
Have fun and good luck!Code:pendrivelinux.com/live-ubuntu-810-usb-persistent-install-windows/