1. Boot up with the Gentoo minimal cd.

2. Mount your gentoo partitions…

 mount /dev/sda3 /mnt/gentoo

mount /dev/sda1 /mnt/gentoo/boot

mount -t proc none /mnt/gentoo/proc

 mount -o bind /dev /mnt/gentoo/dev

mount --rbind /sys /mnt/gentoo/sys

mount --rbind /dev /mnt/gentoo/dev

3. chroot into the install gentoo environment…

cd /mnt/gentoo

chroot /mnt/gentoo /bin/bash

env-update

source /etc/profile