You can use FDISK by booting with a Windows 98 or Me start-up floppy. run
FDISK and then Delete Partitions->Delete non-DOS partitions. After deleting
the non-DOS partition (which is how FDISK sees XP's NTFS format) then use
FDISK
to Create Partition->Create Primary Partition. When finished reboot and run
FORMAT C:
or you can use the XP CD. Boot with the C D and select the option to Repair
with the Recovery Console (first screen press 'R') You will enter you
Administrator password if you must but often just pressing the Enter key
will provide the default needed to enter the Recovery Console. You will see
a command prompt.
To Format type at the command prompt
FORMAT C: /FS:NTFS
or
FORMAT C: /FS:FAT32
depending on your preference
****Note If you want to repartition before you format then at the command
prompt type DISKPART and press Enter and follow the on screen instructions.
When finished with the Recovery Console type EXIT at the command prompt and
the computer will reboot.