When you first start Ubuntu you need to press the escape key and append "noapic nolapic acpi=off" to the boot options. Your computer is an older model apic isn't compatible with it. My dad's computer is the same way. If you ever get around to installing it on your harddrive you're going to have a doosy. You'll have to go into a liveCD, mount your harddrive as if you were actually using it and then edit your bootloader.