I think i need a Steering Rack

[Crysis]

For the last couple of months there has been a rattle from my front end when I go over bumps in the road(big or small) and now my steering is getting difficult to turn periodically. I did some reading on the website and figured it was the o-ring and so I replaced that, but I think it may be the steering rack. By replacing the O-ring I got rid of the shudder in the steering, but it still will randomly become difficult to turn. Plus, there is a very bad vibration in my front end when I am at high speeds. I had a mechanic check my alignment and he claims it looks fine and I also rotated my tires, though the problem still persists. Any help?

P.S. When I jacked up my car to see if anything was loose I noticed that both of my CV joint boots were torn; could this cause the shaking in the steering wheel?

Aaron