I've got a HP Pavilion ze2000 with a fresh install of Ubuntu 12.10 and after I got my wireless working, (12.10 HP Pavilion ze2000 wireless doesn't work) I'm ready to tackle this GRUB menu issue. From a cold start or on reboot, I have to CTRL+ALT+DEL to get the GRUB menu to come up so I can boot. At first I would power off then back on to get it, but after a while I figured out that CAD works as well.
sudo apt-get update and
sudo apt-get upgrade so everything should be up to date (I think). This is my first Ubuntu install but I have played with a couple other linux flavors.
After the GRUB menu comes up, the machine will boot no problem.
Any ideas? Thanks.