The CD should be set as "Auto" in BIOS. Connect 1st HDD as primary/master, 2nd HDD as secondary/master, and the CD as secondary/slave. Make sure the jumpers on these are properly set. Now go in BIOS Setup and auto-detect the HDDs. Probably the CD won't be detected. Set the rest (primary/slave and secondary/slave) to "Auto", save the settings, reboot. Examine the POST screen while booting (use the Pause key if necessary) The BIOS should show something like "Secondary Slave : <CD drive model>" If it does, then everything is fine. However, if it doesn't and Win98 doesn't detect the CD too, consider putting both HDDs on the primary controller. You could also try looking for a BIOS update. Write down the number you see at the bottom of the POST screen and look it up on the net to find the exact mobo model, etc.