grub rescue
 

Hi I have run fsck and after reboot I've got grub rescue promt
I'm using ubuntu server with lxde desktop on this htpc
ls gives me this partitions (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos1)
when i run ls (hd0) - unknown filesystem , and that is for all partitions

fsck does have the potential to corrupt file systems when it attempts repairs. Did you notice any thing in the fsck output about any repairs it made?

What prompted you to do that? Problems with the server? What problems? Was this server up and running for some time? A new install?
Do you have an Ubuntu or any Linux Live CD? If you do, the simplest thing to do then to eliminate a lot of guessing would be to use the Live CD and go to the site below and download and run the bootinfoscript which will give useful details about your boot files/setup? Read the instructions first!:

http://sourceforge.net/projects/bootinfoscript/

It will output a results.txt file which you can post here.

I have noticed some changes done by fsck but didn't look to serious to me is there way how to fix this or do I have to reinstall ?

What changes were done by fsck?
What "this" do you want to fix?
You'll need to post more details to get any actual help.

use Live CD get into ubuntu,then rebuild your MBR. then try grub-install...