Make sure you have the driver for your modem or eithernet card (depending on your connection type) BEFORE you start. Any other drivers you may need can be found on the web after you establish a connection.
Insert your Operating System CD into the drive. Restart your system. Go into the BIOS and make sure "boot from CD" is turned on. Save and exit BIOS. When prompted select "Boot with CD-ROM support". At the a:\ prompt change to the drive letter of the drive your OS CD is in. (eg. D:\) When the prompt changes to the correct drive letter type in "fdisk" and hit enter. After fdisk loads "delete primary DOS partition" confirming when asked along the way. After the partition is deleted you'll need to "create a primary DOS partition". Once this is done hit ctrl/alt/del to restart and "boot from CD-ROM" when prompted. You want to format your primary drive when asked and then let the OS installer guide you the rest of the way through.