Windows Vista Installation Help?

Well,It's like this-

I have Windows Vista business, I got it part of my Dell pc.

I've had it for nearly a year, and I want a fresh start to my pc,so I wish to re-install my vista (Format Drive and re-install Vista)

I have made a backup of all my necessary files.

I inserted my vista business cd, and the installation pops up, i click 'install'

There seems to be no option to format my c drive and cleanly install it, and they say i have to boot up my pc with the cd inside in order to do so. I did that,and nothing happened, just my normal booting up process!

I want a way to format my c drive and cleanly install windows vista business, to get a fresh start(which came with my pc by the way, so what's on pc now is what i want to install(or reinstall))

Any help ppplllllzzzz?

if u need any more info, just ask!

ppplllllzzz help!