sata drive does not boot
 

I reshuffled some of my harddrives, removing two pata drives and added a couple of sata ones. now my system does not boot. I do not think this is directly related to linux, but a level below. my system drive is the same as before, the one in the first sata slot.

In BIOS I have set cdrom as first boot device, and then harddrive, nothing new. When I try to boot, I get to the point after POST, I see the line "boot from cd-rom" as usual, but then nothing happens. there is no freeze, system is responsive.

If I tried to swap the sata drives, placing the one with OS in slot 3, the system looked like it got further, getting error 21 from grub.

If you place the drives back the way they were does it boot?
If so post contents of the following files.
/boot/grub/grub.1st
/etc/fstab
And from this command as root. /sbin/fdisk -l

Now place the drives you want to use and if it does not boot then boot from a linux floppy or Live cd and run the fdisk command again and post output.

The IDE drive that is removed is it the first drive the system sees and is where grub exist on the Master Boot Record of that drive?

Brian