Try acpi=off and you should be all set.
The complete steps are:
- when you have the grub menu, select the kernel you would like the sytem to boot (usually the first one) without pressing enter
- hit the key e (e like "edit)
- select the second like (which starts by vmlinuz ... and key in at the end acpi=off
- select the first row and hit the key b (b like boot)
you should be all set
Once you have booted, you can edit the file /boot/grub/menu.lst and add acpi=off --> like this you won't have to punch it in every time
I hope this works
Good luck
Ioan
(http://linux123.org)