There's a 50% chance 'fdisk' won't be able to delete the NTFS (non-fat) partition. I usually have to load win2k, and have it delete the partition, then load win98 on.
You'll type in 'fdisk', and select yes for large disk support. select option 4? 'delete partition'. If you have an extended partition, you'll have to delete 'logical disks in the extended partition' before it will let you kill the extended. Then hit escape back to the 'main' menu, select number 1 'create primary partition', and select the size after the friggin fdisk checks the 'validity' of the disk twice, which takes 5 minutes each run on a 45 gig drive.
I use partition of no greater than 10gig on fat32, and use the following format commands:
format c: /u/c/z:4 (for 2k clusters)
format c: /u/c/z:8 (for 4k clusters)