How To:- Power Steering Failure! Simple fix.
The ignition switch trick normally solves a power steering failure. The power steering has a relay that has a tendency to stick.
Inset your ignition key and rapidly turn the ignition ON and OFF about 10-15 times.
This nearly always frees the relays contacts. Much cheaper than a trip to you local Mr.T!
Also, see this article for an alternative fix.