I ran fsck despite *** SEVERE DAMAGE *** warning, and it did some ugly things, and now I have no grub. (only later I learned the propper way to check disk)

So I restored mbr with win xp setup disk.

Is it fixable?

I tried with linux live (knoppix) but I've got nowhere.

Have a look here:
https://wiki.ubuntu.com/Grub2

I dont have ubuntu cd but I do have some old live cd: knoppix.

From there, I can run grub, grub-install, mount and such.

Lost partition is /dev/hda2 but can not be mounted:
mount: wrong fs type, bad superblock, or too much mounted drives [sic]
Why is that?

...I have no problem mounting /dev/hda1 (ntfs)

grub-install reports something like unable to write /boot/grub...

fdisk says nothing is wrong with the partition.

Once I boot linux from hard drive it should be easy to upgrade grub2 from there.

So, how do I set up old grub, not grub2?

All you need is a live cd that uses grub2, an old knoppix cd will probably have grub legacy. ubuntu uses grub2 and a few others. Which distro do you have using grub2?

Here is some documemtation and link to download grub2.

grub2

What distro is on /dev/hda2? Knoppix? What filesystem is on /dev/hda2, ext2, reiser ...?
If you cannot mount the OS partition then you won't be able to restore grub. So you have to fix this issue first.
And please give more info on the commands that you issued and what the result was.

Seems to me there are two problems here.

(1) The Partition hda2 where Linux is residing is corrupted and cannot be mounted.

This is a killer. If you you cannot mount the Linux partition you cannot restore Grub2 as it needs the hard disk address of its second stage core.img.

(2) The source of Grub2 is unclear.

AFAIK Knoppix is nowhere near offering Grub2 so the original distro CD or DVD should be used. Although the package installer can install Grub2 but some supporting files may be missing if the distro has been configured to run only Grub1.

If the above are true then a re-installation can be more productive.

Looks like the partition (was) corrupted.

No further help required, thanks people!

And my advice to all:

BEWARE of disk check, mind the warnings

But maybe it wasnt diskchecks foult, since there was loads of bad sectors on this disk.
This being an old notebook and all... so suprise.