17" Macbook Pro OS X Lion stuck on 'mac logo' and spinning wheel screen?

I bought a 17" MacBook Pro, 3 years ago and since updating my OS X to latest version 6months ago, my mac has crashed 3 times and needed a full reinstall of the OS X 3 times. I would like to know if OS X latest updates has been a problem for other MacBook Pro 17" users? Is it worth installing older version of OS X to avoid this problem, or could it be something else?

Is there away of avoiding these crash issues, which I have been told may have something to do with "corrupt root directory files"?

Does anyone know how to find step by step instructions on how to reinstall OS X on a crashed mac at home, instead of sending to expensive authorized mac service centers? What do I need to restore a crashed mac and can I download what I need to reinstall from the internet?

I hope someone has been able to resolve this issue I'm experiencing and is happy to share their knowledge with me.

Cheers,

Opie

opiesayner@gmail.com