this will require a reinstallation:
1.u should try to install lilo on the first sector of boot partition(which must be on the second hrd drive ,right?).then do the following..
use ur boot disk to get into linux.and do follwoing .
copy a file called to the bootsect.lnx to the floppy using command
dd if =/dev/hdb5 of=/bootsect.lnx bs=512 count=1
mount /mnt/floppy
cp /bootsect.lnx /mnt/floppy
umount /mnt/floppy
here i have assumed that ur boot partition is /hdb5 so replace it with ur's one.now exit from linux and get into xp.edit a file called boot.ini and at the end put follwing lines there.
c:bootsect.lnx="linux"
save the file and reboot ur system.now enjoy a dual boot system.
2.try to install grub on the mbr.rest will be taken care by the grub iteslf.don't worry that grub won't allow to boot in to windows.
THIS IS A VERY COMMON PROBLEM.INFACT I AM SICK OF TYPE THE WHOLE THING AGAIN AND AGAIN.SO I AM PUTTING THIS ON MY WEBSITE
http://geocities.com/anandstupid