Simply do the following when you need to do some repairs:

1. Boot from the cd
2. mount your root partition to /mnt ( mount /dev/sda1 /mnt)
3. If you have additional partitions for boot,usr, var etc etc mount them as well
4. cd /mnt
5. mount -o bind /proc proc ; mount -o bind /sys sys ; mount -o bind /dev dev
6. chroot /mnt

Done