I have installed Ubuntu Precise 12.04.2 (64bit, Linux 3.5) on a Samsung Z700. I did update the BIOS and disabled the UEFI before the installation (GRUB does not go the EFI mode, so that's good). Booting Ubuntu from the USB thumb drive works fine, but it refuses to boot once it is installed. I do get beyond GRUB, and then it freezes at the first purple screen (the one without moving dots). When trying to boot into "safe mode", it freezes at
Switching to clocksource tsc
I did some research and found this and this. However, I cannot get it booting. What I don't understand: why can it boot from USB, but not once it is installed? How should I approach this? Can I boot it in the mode that is used to get it booted from the USB?