You could try 'un-installing' or 'removing' Ubuntu completely from your HDD. You can do this with Gparted from Ubuntu DVD/USB and delete all partitions, and recreate them. If you have a separate 'recovery' partitions and 'Samsung utilities' and if you want to preserve them, then just delete Ubuntu partition and recreate it. Perhaps then you can get to the Samsung screen. OR you can contact 'Samsung Service' and get their help to enter BIOS, or recover Windows8 as it was before you removed it. So that we can later remove it accordingly.
Have you installed 32bit Ubuntu on 64bit machine? Or is you machine 32bit? I don't like 'pae' at the end of that kernel line. PAE.
GNU Grub version 1.99-21ubuntu3.9
ubuntu, with linux 3.2.0-40-generic-pae
ubuntu, with linux 3.2.0-40-generic-pae (recovery mode)
Previous Lniux versions
MEmory test (memtest86+)
Memorty test (memtest86+, serial console 115200)
I suspect that your Ubuntu 'old version' is 32bit and your machine is 64bit, that is why you have a 'pae' kernel. The 12.04 you have downloaded, is it 32bit or 64bit? You must download 64bit Ubuntu. Please confirm this.