>From the first post, you've ran, under grub, setup (hd0,0). This installs grub on the first partition boot loader, you want to install it on the DISK boot loader, on the MBR. Maybe gparted fixed that for you. The correct way would be to run: root (hd0,0) //indicate where grub stage 1.5 and 2 are. setup (hd0) //install grub's stage 1 on the MBR.
About the second error, the kernel is definitely detecting your sata controller, the partitions are all there. It seems that you missed to append the root=/dev/sda3 to the kernel parameters, under grub.conf. In the end, I'd recommend disabling ext2 fs support in the kernel too, and use ext4 to mount ext2 and ext3 file systems.
