Simply do the following when you need to do some repairs:
1. Boot from the cd
2. mount your root partition to /mnt , if you have lvm paritions use vgchange -ay first.
3. If you have additional partitions for boot,usr, var etc etc mount them as well
4. mount -o bind /proc /mnt/proc ; mount -o bind /sys /mnt/sys ; mount -o bind /dev /mnt/dev
5. chroot /mnt