Vista Won't Boot From Grub Under F11

[rgheck]

I've just installed F11 on my wife's machine, which is some cheap 
Gateway thing. Everything is working fine except that Vista (I'm hoping 
to be able to get rid of it for her, but not yet...) will not boot from 
grub. It starts to boot, then dies and dumps me into the System Recovery 
thing. I was able to restore the MBR as Vista wants it to be, and then 
it would boot fine again, and so I can use the popup boot chooser either 
to boot Vista or to find my way into grub. But this is not really what I 
want. I'd rather just use grub.

I've experimented there will various "root (hdx,y)" settings, but none 
of them allow me to boot Vista: Same thing happens.

More info:
* Vista is on the first hard drive.
* There is a /boot partition on the second hard drive, which is also 
where F11 lives.
* I've had to use acpi=off to get the keyboard and mouse to work (either 
USB or PS/2).

There is something odd happening with the bios mappings. Although grub 
is on the second hard drive, I have to use (hd0,0) for the splash image 
and also for the "root" argument to get F11 to boot. Nonetheless, once 
F11 does boot, its own drive appears as /dev/sdb.

The device.map nonetheless maps /dev/sda to (hd0) and /dev/sdb to (hd1).

Any helpful ideas?

Richard