Been a long time since Ive installed Win98, but here is the best I can remember. Backup all your data you want to save and get out your Win98 boot disk. Boot to the boot disk and at the A: prompt type fdisk.. then select to view partitions, then delete partions.. delete ALL partions and logical drives untill it says there are no partions to view. Then create the Primary DOS partition, once the Primary partition is created you will have to reboot and once again booting to Win98 bootdisk, selecting with CDROM support. At the A: prompt type Format C: and it will format the drive for Win98. Have your Win98 CDROM in the CDROM. After Format is complete then at the A: prompt type setup and Win98 will begin installation. You will need your installation Key from the CD when it prompts for it. This is assuming you have a full version Win98 installation CD with Key.