The original Vista CD will do the formatting and installation for you. If you put the CD in and restart your computer you should see a message "To boot from CD press any key..." If you do not see this message when your computer restarts, restart your computer again and hit delete or F2 (depends on your computers make) to get into the BIOS menu. You must change the boot device order so that your PC tries to boot from your CD drive first, before the hard drive.
You can go from here following the step by step instructions that Windows provides you. Be warned though, that when you format your PC you will lose everything (when choosing formatting options don't choose quick)
You will also need all new drivers for your PC which you can get online before you ever format your PC. On the backside of your computer it should say make and model number if you use Google you can easily find the proper drivers from the manufacturers site: BE WARNED A LOT OF WEBSITES OFFER DRIVERS THAT ARE ACTUALLY NOT DRIVERS & CAN CONTAIN MALWARE. Make SURE you go to the manufacturers website when obtaining drivers. After you've downloaded the drivers burn them on a CD or DVD or put them on a USB stick. They are all .exe files and will easily install once Windows has loaded.