My Hive has no eggs, larva, capped brood, or laying queen?

First, make sure you are able to spot eggs and larva. See “Tips for spotting eggs & larva”. If you are confident there are no eggs, larva, or capped brood, then you almost certainly have a queenless hive. The most important question at this point is how long have they been queenless? 

1. If there is still capped brood in the hive, then there is a good chance the hive has a virgin queen that hasn’t started laying yet, but should soon. Give the hive a frame of eggs and larva from a stronger hive (see how to here), and check back in 2 days. If they are beginning to raise queen cells all over the frame (see “Queen cells vs queen cups”) then they are queenless, and you will need to add a queen. If they don’t raise queen cells, give them another week, and you will most likely begin to see eggs from a new queen. If you don’t, give them another 2-3 days. If there is still nothing, then proceed with adding a new queen. If you don’t have a frame of brood to give the hive, just wait another week then check back for eggs. 
2. If they have no brood, not even capped brood, they have been queenless for at least 21 days. In that span of time they should have been able to successfully raise a new queen, and she should have begun laying. Assuming your hive is strong enough to survive (see “When to give up on a hive”) then give them a frame of brood from a stronger hive (not necessary if you don’t have a second stronger hive) and give them a new queen as quickly as possible. Check out how to install a new queen and “Ordering & receiving queens".
3. Purchase Queens Here