error 18

[Koen Segers]

        I'm working on gentoo for 2 years now. I still have a dual boot with 
windows
xp. Today (after many months) my sister needed windows. I rebooted but I
got the strange error 18 on my screen. In documentation of grub it states
that this is a problem with BIOS. Strangely enough there was no problem
before. Any idea what could have caused this error? Maybe an update of
grub?

my current version is:
$grub --version
grub (GNU GRUB 0.96)

It is impossible to look in the logs because it might be a problem that
exists for many months as I have never booted windows since...

This is my grub.conf:
$cat /boot/grub/grub.conf
default 0
timeout 10
fallback 1
splashimage=(hd1,0)/boot/grub/splash.xpm.gz

title=gentoo linux 2.6.12-r9
root(hd0,0)
kernel (hd1,0)/boot/kernel-2.6.12-gentoo-r9 root=/dev/md0 floppy=no_acpi
gentoo=nodevfs

title=gentoo linux 2.6.12-r6
root(hd0,0)
kernel (hd1,0)/boot/kernel-2.6.12-gentoo-r6 root=/dev/md0 floppy=no_acpi
gentoo=nodevfs


title=Windows XP
rootnoverify (hd0,0)
makeactive
chainloader +1


fdisk of my 2 hdd:
$fdisk -l /dev/hda
Disk /dev/hda: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1        2550    20482843+   7  HPFS/NTFS
/dev/hda2            2551       14946    99570870    5  Extended
/dev/hda5            2551        4375    14659281   fd  Linux raid
autodetect
/dev/hda6            4376        4388      104391   82  Linux swap / Solaris
/dev/hda7            4389       10468    48837568+  fd  Linux raid
autodetect
/dev/hda8           10469       14946    35969503+  fd  Linux raid
autodetect

$fdisk -l /dev/hdc
Disk /dev/hdc: 122.9 GB, 122942324736 bytes
16 heads, 63 sectors/track, 238216 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1         195       98248+  83  Linux
/dev/hdc2             196      238216   119962584    5  Extended
/dev/hdc5             196       38755    19434208+   b  W95 FAT32
/dev/hdc6           38756       67820    14648728+  fd  Linux raid
autodetect
/dev/hdc7           67821       68015       98248+  82  Linux swap / Solaris
/dev/hdc8           68016      164897    48828496+  fd  Linux raid
autodetect
/dev/hdc9          164898      238216    36952744+  fd  Linux raid
autodetect

Plz help