Comment 21 for bug 576204

Dr. Kenobi,

To change the kernel options at boot time, power up your system and hold down the 'Shift' key while booting. This should bring up a grub menu, where you can press 'e' to edit the current boot options, then press Ctrl+X when finished to boot.

You will probably also want to test booting with acpi=force as an option, as described in comment #15.