Power Steering Problem

I have a 1998 Buick Regal LS with 113500 miles on it. It has an automatic transmission with front wheel drive. I made a hard right turn to back out of a cul de sac. I then had an immediate problem with the power steering not working when the wheel was turned to the left. I checked the fluid and I did add some, but...turning the wheel right and left to bleed possible air bubbles hasn't worked. Could I have I put the steering wheel position sensor out of alignment? I don't want to remove the pump or the steering rack just to go on an expensive fishing expedition to find the problem.