Last night I went to start my car, and the key would only turn a small amount and refused to go further. I eventually got my ignition apart, and after investigating it for awhile and trying different things, I determined that the problem was that this little metal cover that keeps tension on a spring had popped loose, and when that happens, no turning of the key.. The cover has a small tab in it that presses in to this catch on the main key cyclinder, and that catch had worn down so much it was actually rounded. All I had to do was take a small file and file it square again so the tab in the cover would fit.



That little gold bar can be a trick biotch. Pay attention to how it fits in there, because it fits fine like three different ways but only one is correct, and you CAN get that shiny silver cover stuck on there.. The little tab, with three flat sides, goes down in to the cylinder, and the half arrow shaped end goes towards the front, where you insert the key. The spring sets in that groove, and the cover slides on and a little tab in the top of it locks it in place..

Here is a close up of where I filed, and the little tab in the cover:

 

Glad you got it fixed!