Before the upgrade, booting did not work out of the box, but this site told me to put "acpi=noirq" before "quiet splash" in the commands befre startup, and edit /etc/default/grub too. This worked perfectly in 12.04, but when I upgraded to 12.10, things went wrong. The commands are as they were before ("acpi=noirq"), but the default booting option doesn't work. I have to choose advanced options and then the old kernel. Bumblebee and everything else works fine, but it isn't secure to rely on an older kernel version, and it's very annoying that I can't just start my computer and wait som seconds. Can someone help me, please? (I'll try to write "acpi=off" instead, but I don't know if it works.)
In addition: Yesterday I found that before "acpi=noirq quiet splash" there is this text: "ro". When I removed that, everything worked perfectly and I were able to boot normally. Today I did it again, but it didn't work. I also noticed that "acpi=noirq quiet splash" is repeated, and there is a meaningless mix of numbers and letters at the end of two lines and before "root=(something like UUID)=".