Why is my power stearing not working?

Belt fell off or the power steering pump is worn internally. If the pump is worn, the power assist will come back when you increase the engine speed.

Seals can be leaking inside the rack and pinion steering gear too. That will almost always affect turning in only one direction first. Turning the other direction will also be affected a few weeks later as other seals start leaking internally. The leaking seals will expand when the power steering fluid warms up after anywhere from a few seconds to a few minutes, then the power assist will come back.