No SIM card or no service? Worlds of difference. If it's in fact displaying "no service" it's because the card itself was removed from the provider due to non use. If however it is as you say, displaying "no SIM card" then either it's in wrong and not all the connection points are touching, or it's damaged. Alternatively your phone may be damaged.
Try inserting a friend's SIM card and see if it reads "restricted/SIM network locked" across the top. If the phone is unlocked, it should show you have service instead.
If it works with another SIM, consider just buying a new one as your current card is damaged. They only cost $10.