The interesting stuff starts a couple of pages down:
http://www.pcworld.com/article/261702/how_to_securely_erase_your_hard_drive.html
Do bear in mind, scrubbing a HDD will take quite a long time.
Unless you have sensitive data on the drive the easiest way to prepare it is, as has been said, to just format it during the Windows install in detail:
With the system fully assembled start it up and let it do whatever it wants, wait until it stops booting or halts with a Windows error.
Insert your install disc. **
Power down (if it halts with an error, just turn it off) and wait for a slow count of thirty. **
Power up but during the startup get into the BIOS, consult the motherboard manual as to which key to hold.
Once in BIOS change the boot order so the DVD drive is selected as first boot device, then select the 'save the settings and restart' option, again, check the motherboard manual.
The system should now start from the DVD drive and you'll begin the install process.
After a few screens you'll see one that offers you a choice of which drive/partition you want to install to.
Delete ALL the existing partitions until the screen shows just one, large volume.
Here you now have a choice you can create several partitions on the single disc (Windows will treat each partition as a separate disc) or just to format the entire disc as a single volume.
Select your chosen partition, use the 'format' option and wait until the operation is finished, the screen should now show two partitions: One very large one and a much smaller one marked as 'system reserved'.
Install to the partition you just formatted.
Once the Windows install is finished, restart and change the boot order so that the system boots from the HDD, again, save and exit the BIOS.
If you don't change the boot order, the install will start all over again, if you see that happening, remove the install DVD and do a reset using the power button.
Once the Windows install is over you should install the motherboard drivers: Chipset, Sound, internet, in that order, restarting as required.
EDIT: Substitute 'USB' for DVD and skip the parts marked **