1) # su - (to login as root)
2) # cd /etc/init.d
3) # nmap localhost (to see what all services are running)
4) # service sshd start (to start the ssh service)
5) # nmap localhost (again run nmap to see if ssh has started running)
You can start any services using the "service <servicename> start" command. 'start' can be replaced with 'stop', 'status', 'restart' to see respective results.