Boot to the 10.3 install disk #1, by inserting the disk, and reboot while holding the letter C.
After the screen where you select a language - choose Disk Utility from the Installer menu.
Select your hard drive, and choose the erase tab. And, erase the hard drive. You can choose to enter a name for the volume if you like.
Quit that Disk Utility, and continue on with the OS X install. Follow the directions on the screen. Replace the disk #1 when asked, possibly to disk 3 if you install other printer drivers.
Should be that simple....
Serendipity is a lucky guess !