useless product

I purchased an Hp Q58 laptop in Aug 2013 from mtn, however, have now had 3 hard drives crash every 6 months which Ensure It, supposedly the accredited service workshop, tell me is quite normal. The laptop is also extremely slow, which I am also told is quite normal, yet everyone I have spoken to says they have never had to replace a hard drive in any laptop they've had and that the speed of the laptop can be sorted out. I believe that Hp should either take my laptop and get someone who knows whatbthey are doing to sort it out for me free of charge (and not Ensure It), alternatively, replace my laptop with a new one that does work properly or better still, refund me every cent I've spent. Never have I been so angry with a purchase in my life.