1. Do you still have files on there u wanna keep? If you do, DONT format or fdisk until u get them off.
2. Do you have the CD drivers? Make a 98 boot disk. You will be able to boot from it and it will install the drivers.
3. If you're NOT tryn to save the files on your system, just boot from the 98 disk, format C: Then place your CD in the drive and at the drive letter prompt type SETUP, and you'll be on your way.
3. If you ARE tryn to save file, and you've got the 98 disk disk, blow away the windows directory (you'll have to reinstall your old programs but you're gonna have to do that any way). Also, blow away the "setup" files on C: You should be able to install a new copy of 98 now.