It's really frustrating.

Three week's back story:

I faced the following error on ubuntu 10.04 LTS Desktop,

error : unknown filesystem
grub rescue>

I tried many solutions online apart from 1 and 2 and eventually I could not boot my system at all. Trying those solutions could not completely fix it and then I had to face initramfs(could not remember exact error).

As I could not fix, a week back I did a fresh install of Ubuntu 12.04 Desktop and after a week i.e, now, I got the same grub rescue> error. Could anybody tell me what's the reason behind this error?. Is there any problem with the Ubuntu or it's a problem at my side due to some reason?.

My machine description:

I have two hard disks, windows is installed on one hard disk and on another it's Ubuntu. I installed the operating systems(vista, ubuntu) such a way one is not known to another, I mean to say, I'll unplug one hard disk and install the Ubuntu and similarly I'll unplug the ubuntu hard disk, installed the vista on another hard disk, generally I do(I actually don't want to run into grub/boot.ini issues installing OSs connecting both the hard disks). When ever I power on the computer windows will boot by default, and I'll generally boot to ubuntu by pressing F8 and selecting the ubuntu hard disk.

Any help is greatly appreciated!. Thank you!