What are you going to reinstall from?
If you have a retail copy of Vista and install again from the CD's/DVD's it should
give you the opportunity to format and/or repartition your hard disk during setup.
I don't know what happens if you re-install from a recovery partition like DELL and
HP provides with new PCs, rather than giving you a backup copy of Vista on CDs.
You could create a bootable rescue CD such as SystemRescueCD and use its tools to
format the disk. GParted knows how to format a NTFS drive.
http://lifehacker.com/software/geek-to-live/partition-and-image-your-hard-drive-with-the-system-rescue-cd-292972.php
http://www.sysresccd.org/Main_Page
