The simplest thing is to boot using your SuSE DVD (or CD) and cancel out of the installation process and select either the "boot installed OS" (not at a linux box, so this is from memory), or a second similar choice (a little help here folks...)
Anyways, this tells SuSE to boot up your already installed system by telling which partition to boot. From there you can repair & rerun grub.
As for your grub config file, this looks fishy:
title Fedora Core 2 test 1 (2.6.1-1.65)
kernel /boot/vmlinuz-2.6.1-1.65 ro root=LABEL=/ rhgb
title SuSE Linux 9.0
I can't help but notice that you don't seem to have a kernel in mind when you are booting into SuSE. Details, details...
So if I get this right, you can boot into Fedora?
If so, boot into Fed and mount your SuSE partition (/dev/hda2 it appears) and get the names of the SuSE initrd and vmlinuz files that you wish to use (hint: you can purloin this info from the /SuSE/boot/grub.conf file that resides on the SuSE partition. Just replace the /SuSE with the actual mount point or partition).
Add these lines into your /boot/grub.conf using the absolute path to the files (alternatively you could copy these files over to the Mandrake side) like this:
Notice that you can use both the old method of describing a partition (good) with the new way (evil)?
Not that I have a preference... Actually, I still wonder how grub is better than lilo. Shrug.
Save the file (you did make a backup first?), run "grub-install /dev/hda" as root.