DBAN Download | Darik's Boot And Nuke
And burn this to a cd, after that shut down your computer completely, wait 5 seconds and then bootup with dban still in your cd/dvd drive (your might need to go into your BIOS to make sure that the cd/dvd drive is the first bootable drive) and then select your harddrive to wipe clean you will need to wait until it is 20-25 percent done and then all you need to do is just press your reboot/shutdown button on your computer, take out dban and replace with your Windows os and reboot.
Hope this helps you.
Do you have a physical Vista installation CD or are you trying to restore from a hidden partition on the computer's internal hard drive (ie, pressing F10/F11 on boot-up)?
In your initial post, you said you could not get the copy of windows to boot. As suggested above, you need to set your CD/DVD drive to first boot priority in the BIOS in order to boot from it. If you still are booting to the hard drive as your last post seems to suggest, you need to make that change. When you boot the computer, you should see a message on the screen telling you which key to press to enter the BIOS or to enter Setup. After doing that, you should be able to boot the installation media.