Reformatting mac hardrive?

[tom26]

I posted this in the hardware forum but guess it may be more suited here:
I don't know whether any of you will remember but I managed to buy a used Mac for £50 a week ago. Knowing absolutely nothing about Macs, I was advised that the hard drive needed reformating and that the discs weren't with the machine. Does anyone know firstly how I reformat and secondly where I get the discs from to reformat?

Thanks

 

[tom26]

Snow Leopard might still be available from Apple Stores until Lion is available in physical format. I've not been down to one recently.

Can your Mac take Snow Leopard do you know? It needs to have an Intel chip.

It has an intel core due processor, so I would take it that means yes?

Is it just a case of buying the latest operating system and then I can use this to wipe everything effectively?