It seems everyone else has got the exact opposite of my problem. They can't boot from Live CD but not other way around as I am...or at least that's what I'm assuming the problem is.
Here's what I did. I have an acer iconia tab w500 tablet (windows 7) with dvd-rom, 1TB usb3-hard drive and other stuff connected to it via USB, like a finger scanner) and I decided to try Ubuntu on a tablet.
Burn the ISO to a DVD, booted from DVD, partitioned it to
ext4 with swap and installed but soon as it restarts its just keep booting from the Live CD and not from where it s installed (the 1tb hard drive).
If I take the cd out, it just gives error like "can't found live cd source". By the way there is already Windows 7 installed on tablets internal storage(32GB)
I installed Ubuntu on the external hard drive, so on the boot screen it asks which OS I want.
Before the installation the, tablet didn't boot from the Live CD and straight opened windows 7. I can't change BIOS settings and see which device is booting first (since I've got no external keyboard to press F2 after pressing correct buttons on the tablet).
I had to choose this option from the Ubuntu Live CD menu in Windows to install this additional autorun setting.