How to reinstall OSX on Macbook running Windows 7?

[BEETROOT]

My brother gave me his old Macbook that is running Windows 7. I want to get rid of Windows and install Snow Leopard.

The problem is that I can't access any of the boot camp options to manage partitions or anything like that. Windows 7 is the only OS installed on the computer. If I hold C when I start the computer, I can get to the dual boot screen but Windows is the only option.

I've tried to access the OSX installation DVD in Windows, but it just ejects the DVD every time I put it in.

Any advice would be greatly appreciated.

 

[alust2013]

Put the disk in when you start the computer, and hold c. This will allow you to boot from the disk, where you can reformat the drive and reinstall OS X

 

[BEETROOT]

OK tried that. I hit the power button and immediately inserted the DVD, then held C. It sits on a grey screen for about 15 seconds while spinning the DVD, then ejects the DVD, then it brings up Windows Boot Manager. I have options to start Windows 7 or run a memory diagnostic test, but still can't get the DVD to run.

 

[blueroom]

Either the drive or DVD disk are bad.