I had grub installed on my ubuntu partition, which I recently deleted as I hadn't used it in almost a year. That left me with XP and Slackware partitions.
Here is the setup
/dev/sda1 < swap
/dev/sda2 < XP
/dev/sda3 < Slack
/dev/sda4 < NTFS space

I tried doing a grub-install /dev/sda (from knoppix live CD, which is where I am now) which looked like it worked fine until I rebooted and got a black grub console.
After searching around I tried this:

source (hd0,3)
linux /boot/vmlinuz ro root=/dev/sda3
initrd /boot/initrd.gz
boot

It goes through the normal boot process until, I assume, the point where it mounts the file systems.
I get the following error:
no /sbin/init found on rootdev fs
Kernel Panic!

any ideas?

I also have no menu.lst or stage1 file in my /boot/grub.

Also, I just checked and /sbin/init does indeed exist on /dev/sda3

try:
Grub starts counting at 0, so (hd0,3) is your NTFS partition.

HTH

Norm

Indeed, that is what I thought, yet when I type (hd0<tab>), it tells me that
hd0,1 unknown file system
hd0,2 unknown file system
hd0,3 ext2fs
hd0,4 unknown file system

I tried hd0,2 anyways, and got the same error.

I am aware that this is not so much a grub issue but rather something else.
I got lilo to work, but I get another kernal panic error:
No filesystem could mount root, tried:
kernel panic- not syncing. VFS:Unable to mount root fs on unknown block(8,3)

I have no intrd file.
I think I remember that this might have been the problem a long time ago.
How can I create an initrd? (If I am correction in my assumption)

To create an initrd file you need to use the Slack disk to boot into your system (instructions on the screen when you boot the disk). Or, boot the Slack disk and chroot to the partion containing the Slack system.

Use the mkinitrd command to create it. There should be an initrd readme file in your /boot directory that explains how to do it.

I made an initrd, but it made no difference
In case this helps, this is what I use to boot from the CD

hugesmp.s root=/dev/sda3 rdinit= ro

And THAT works.

This line is wrong. Don't know where the word source came from but it's wrong.

it should read

root (hd0,2)

If you're using the huge-smp kernel, the one used during installation, you don't need an initrd. You need to create one if you change to the generic-smp kernel.