Deleted c and d

Hi all, bit of a noob over here so appreciate all the help in advance!

I wanted to restore my Dell studio 1555 to factory settings but no longer have the Windows 7 CD and couldn't find the option to restore or repair the pc in the advanced boot menu, so I somewhat rashly used Eraser to delete my C and D drives.

I am now trying to install Vista and then from Vista use a Dell update CD to reinstall Windows 7. I have changed the boot order in the Bios to have the CD drive at the top of the list. The problem is it says 'Windows is loading files' and then the computer crashes, and the same thing happens when I try to install XP. In fact, even when I have the computer on the Bios without trying to install an OS, it just shuts down after a few minutes.

All I want is a fresh install of Windows 7 with none of my personal data on it.

Thanks so much

Adrian