macbook keeps freezing, no start up option working

My macbook pro 13 inch is continuing to give me problems.
Now it is freezing all the time. If I manage to get it on it'll freeze after 5 mins and I have to hard re-boot which usually doesn't work anyway.
If it does turn on it goes to the loading screen where the spinning symbol will freeze.
It even freezes during SMC and PRAM resets and on the Command-S screen.
I tried to load it up using the install disk which also didn't work and now it's stuck in there so I can't run a hardware test.
This has happened before and I had to petition it and reload all the software which helped but now I'm back with the same problem! Is there any way I can get the unit replaced if it KEEPS giving me the same issue? If I go to the apple store they'll just tell me to petition it again..
I have hardly any programs on it..maybe 2 apps, utorrent and mobile broadband software. But I didn't have half of that before and same problem... It seems it gets worse and worse each day until eventually nothing will turn it on. What can this be??
Ahhh please help...!

It sounds like a bad hard drive. If the machine is still under warranty or Apple care, take it on back to your local Apple store and let them deal with it. If you're not satisfied with their diagnosis, ask to speak with a supervisor. Be polite and explain. Chances are they'll change the hard drive for you if it's defective. Before you go, backup your data.