Has your cars power steering suddenly quit working? If so, it could be that your power steering pump has failed. The unit itself may be shot or it could be a loss of steering fluid through a bad hose that is causing the problem. Regardless, you better tend to the problem now or you will soon be struggling with steering a car that seems to be working against you, not with you.
Before pump failure becomes obvious, you will usually hear buzzing or whining noises coming from underneath the hood. On the other hand, if you notice a gradual loss of power as evidenced by an increasingly difficult time moving the steering wheel [as when attempting to parallel park] or if you notice the problem when you first start up your car in the morning, then your steering rack may be going.
Steering racks fail gradually, but when they do you must take action before total failure occurs. Otherwise, control of your car becomes impossible and failure could then happen at any time, as in those times you are on the interstate. A real threat to your safety and to the safety of other drivers!
To find out if it is the steering rack causing the problem, check the power steering fluid...