Not likely bypassing bios, but could be a masked post, like that of a dell or gateway. It ensures the user isn't hosing up their system by meddling around where they don't belong.
Pull the cmos battery for a while (3-5 minutes should be more than enough). Reseat the battery and boot. Hold F1, or DEL or what ever your system requires of you to access the bios. You should get access.
Otherwise, you could try to force a boot error or something like that. Maybe disconnect the primary master HDD from the ide ribbon and boot again. If all goes well, it won't detect grub and will make you modify the bios in the belief that you misconfigured it because it isn't seeing the HDD

Regards and good luck.