Well, if you want to do it completely from scratch, then delete the partition(s), create a new partition, format that partition and reinstall the OS.
The easiest way to do this is to use the installation disc that came with your machine. Insert it and boot up your machine. Watch for the lights on the keyboard; after they blink, hit F12 a few times until you hear a beep. This will bring you to the boot select menu. Here, you'll select to boot from the CD drive. Once done, you should receive a message asking you to hit any key to boot to the CD. Do that and then follow the on-screen instructions. Make sure you format the partition in NTFS, not FAT32.
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I swear, troubleshooting is a science: the best discoveries are always on accident...