|XP won't commit "suicide" (you can't format a drive with XP while using XP). If you're starting over from scratch, you can destroy the partition with the XP disc or another utility such as Delpart:|
Once the partition is gone, insert the Win98 disc, reboot, and allow it to partition and format the drive (preferably FAT32) and install Win98. Realize, however, that if this is a "newer" machine (made in the last 10 years or so), you may have problems finding suitable Win98 drivers for all your hardware.
"Channeling the spirit of jboy..."