I found this on the microsoft website, will it work? Remember, the download
version of windows vista ultimate is not bootable....
To use the Diskpart.exe utility to clean the hard disk, follow these
steps:1. Insert the DVD into the DVD drive.
2. On the disk selection screen, press SHIFT+F10. A Command Prompt window
3. Type diskpart, and then press ENTER to open the diskpart tool.
4. Type list disk, and then press ENTER. A list of available hard disks is
5. Type sel disk number, and then press ENTER. number is the number of the
hard disk that you want to clean. The hard disk is now selected.
6. Type det disk, and then press ENTER. A list of partitions on the hard
disk is displayed. Use this information to verify that the correct disk is
7. Make sure that the disk does not contain required data, type clean all,
and then press ENTER to clean the disk. All the partitions and all the data
on the disk is permanently removed.
8. Type exit, and then press ENTER to close the diskpart tool.
9. Close the Command Prompt window.
10. Click the Refresh button to update the disk selection screen. This step
lists the disk.
11. Run Windows Vista Setup to perform a clean installation of Windows Vista.
I found it here: