Hi all. I have a grub error. It.s saying unknow filesystem so i.m sent on grub rescue screen. What to do, to fix

You can start by indicating which distribution of Linux you are using.
The grub error you are reporting means an incorrect entry in the boot menu.
Use a Linux Live CD, open a terminal as root and enter this command to get partition information:

fdisk -l (lower case Letter L in the command)

If you are using an Ubuntu derivative, prefix the command with: sudo

Posting the contents of your grub menu would be helpful. Post the partition info and if you do not know how to mount partitions to access your grub menu file, someone here will be able to explain it.

I am using backtrack 5

Use your installation CD or any Linux CD to open a terminal to run the command I suggested in my last post to get partition information.

Check the /boot/grub/ directory on the disk to find either a menu.lst or grub.cfg file. I don't know which Grub Backtrack uses so post whichever you have. You will have to mount your Backtrack partition to access this information. If you don't know how to mount partitions, post back and someone will explain it.

how do i mount my backtrack partition? cause i've been trying to do so last night, no success.

And thanks for the replies

We will need the results of the command 'fdisk -l' (small L)

It will tell us your partition numbers.

Then we will be able to help you mount your partition.