Format Mac OS X Snow Leopard

Hello all.

I bought a macbook pro in July 09. A few weeks later, I received Snow Leopard and I installed it. My son installed a bunch of crappy programs et my machine is really slow. I'm planning to format my hard drive this weekend.

What are the steps I need to follow to properly format my mac knowing the fact that my Snow Leopard is an upgrade DVD version.

Thank you for your help.

 

Thanks lordjimy but in my case, I bought my mac with Leopard installed on it, I did an upgrade with an upgrade dvd to snow leopard. My questions is: "what dvd should I use to do a complete format on my machine and reinstall snow leopard afterwards.

The apple store told me to insert the leopard dvd provided with the mac when I bought it and use it instead of using the upgrade version of snow leopard.

Please help I'm confused.