Grub

This should update the MBR correctly:

root (hd0,0)
setup (hd0)

Booting from the grub prompt:

root (hd0,4)
kernel /boot/vmlinuz-2.6.21-1.3194.fc7 ro root=/dev/sda5 rhgb quiet
initrd /boot/initrd-2.6.21-1.3194.fc7.img
boot

Grub is a bloody pain. It is a boot loader, but it is a bloody pain.

Assuming that you somehow:

1. manage to create a grub bootable CD
2. manage to resize / re-partition your hard drive which came with Windows pre-installed
3. install Fedora Core 7 without installing grub onto the master boot record.

To be able to boot into your linux distro:

1. boot to Windows. google for "Fedora Core 7 vmlinuz".  This gives vmlinuz-2.6.21-1.3194.fc7.
2. insert your grub bootable CD into the CDROM drive
3. reboot
4. configure your BIOS to boot from CDROM
5. reboot

At the grub screen, hit 'c' for command line, then figure out which device your kernel is located on:

find /boot/vmlinuz-2.6.21-1.3194.fc7

This yields:

(hd0,4)

Now type:

root (hd0,4)
kernel /boot/vmlinuz-2.6.21-1.3194.fc7 ro root=/dev/sda5 rhgb quiet
initrd /boot/initrd-2.6.21-1.3194.fc7.img
boot