I was using grub first, installed in MBR, but when it didn't work I then tried LILO, also in MBR, but that didn't work either.
For the root filesystem I have an ext3 filesystem on the 3rd partition. I was using the default vector kernel. The MD5 was correct, plus I've installed Vector on 3 other similar laptops with the same installation media without a problem.
The root partition is not being found, so either the
partition map is wrong or the file system is not
compiled into the kernel.
This is exactly what I would expect the problem to be, but of course the default vector kernel has sata and ext3 capabilities, and the disk has a very simple partition scheme:
[ACER RECOVER 9GB]::::[VISTA - NTFS 50GB]::::[EXT3 Linux / - 50GB ]::::[SWAP 1 GB]
The installation disk recognized these as sda[1-4]. As I mentioned before I can boot sda3 from the installation disk with "linux root=/dev/sda3 ro" so I can't see why the kernel on the hard drive, which is bit for bit exactly the same as the one in isolinux/sata (I checked), would get confused.