The steering wheel of my BMW 325i, 1993 model will not turn and its locked.the key will not turn also.

Try turning the steering wheel a bit and holding it so that it takes pressure off locking mechanism. Then turn key. When I first got my 530 I had to call the dealer to figure this out.
Hopefully it works for you.

turn steering wheel hard back and forth while trying to turn key sounds like the steering lock tab causing problem

sounds like the key may be worn out..check the appearance of it if it is worn a little smooth that could cause the problem you're describing.

force turn key wiggle steering wheel at same time if wont turn lock needs replaced or repaired,if turns may no work again and needs replaced.

First if the airbag is present, disable it and remove the airbag module. Remove the steering wheel and steering lock and spacer sleeve.Remove lower and upper column clamp bolts. Remove upper and lower column retaining bolts and remove the assembly. Reverse these step for installing. You can get quality replacement of steering column at http://www.carsteering.com/steering-column/

The steering will have a few degrees of play, even when locked. Pull the wheel down(or up whicheer is easier) and turn the key.

The steering lock jams the key in there. If the wheel is turned to the left, turn it further to the left and turn the key.

WHEN INSTALLING THE IGNITION SWITCH IT SHOULD BE INSTALLED IN THE STEERING WHEEL LOCK POSITION.

It might be a faulty power steering pump. Try checking the level of the power steering fluid. It is probably best you have your power steering system checked by a mechanic.

Does the noise occur only when the vehicle is moving?

Try moving the steering wheel from side to side, while stationary (but don't do it too often, or you might damage something). If the noise is still present when the car is stationary, then it probably is the power steering system.

If the noise only occurs while the vehicle is moving, it could be a problem with the differential/final drive, or even wheel bearings.

when looking at the engine with the hood up, look to the right hand side for something that looks like this (#1 in the pic): http://www.realoem.com/bmw/showparts.do?model=ET37&mospid=47720&btnr=32_0957&hg=32&fg=20

it will be black in color, but don't confuse it with the oil filter housing. power steering reservoir will have a unique cap (#2 in the pic) that can be removed with your hand. the one that has the large nut on top is the oil filter. remove the cap and put in the correct fluid.

hope this helped.

Make sure you check your power steering fluid... if it's even low, it will make a terrible noise...run it on empty too long and your can ruin your power steering pump.