This program removes all partitions from a PC hard drive, regardless of the operating system, utility, or virus that created them. This program can be run from a command prompt after booting from a floppy or system startup diskette (see screenshot). Once partitions are deleted, new partitions can be created using Microsoft FDISK so that a new operating system can be installed on the hard drive.
More info:
hxxp://www.meixler-tech.com/pzapper/

Edit: Lol, I got my reply regarding TrayFactory placed here by mistake...

About Zapper there isn't much to say, except of course it's worth mentioning that you can have a free utility from IBM that does the very same thing.