This is how I clean out my disk, I also follow this procedure with a new hard drive.
First of all get a good win98 boot disk.
If you can find the hard drive installation program that would help. Seagate=SeaTools, Maxtor=MaxBlastPlus2, etc.
I personally use MaxBlastPlus(1) on every drive.
1. pop in boot disk, type in fdisk and follow the menu,
enable large disk support [Y] (Y=fat32 option, N=fat16 option)
Type 3 Delete Existing Dos Partition
Type 1 Delete Primary DOS partition
Type 1 Select Primary Dos Partition
Type Volume label listed or leave blank if none
Type Y verify deletion
If you have Extended Dos Partitions, delete them as well.
2. reboot (ctrl + alt + del) type in fdisk /mbr
3. type in fdisk and follow the menu (same as above)
Type 1 Create DOS partition or Logical DOS partition
Type 1 Create Primary DOS partition (use all for entire disk or use some if you want to create additional partition)
Create additional partition.
Type 2 Create Extended DOS partition
Type 3 Create Logical DOS drive(s) in the Extended DOS partition, repeat as needed for each additional partition.
Reboot.
4. Start installing windows.
--------
ok thats the standard way that takes approx 20-30 min on 30gb hard drive. Here's the fast way
Do step 1 & 2, skip step 3, instead reboot with hard drive installation program and go to the partition program and type in what kind of partitions you want, the size, what type of os and the program may ask you to insert the boot floppy and less than 5 min later you are done and ready for step 4. (ps do not load EZ-bios program unless you need it)
If you have a virus, selling the drive, have more time, or just paranoid, you might want to erase the drive prior to fdisk, there is a good program called eraser that is freeware and must be used in windows. Another program is ontrack data eraser and is not freeware, however you can get this for free using IBM installation program (I think its on there, the program itself works in dos and doesn't work with all drives.) I think Seagate also has one.
Good Luck!!