You could always create recovery disk and format from that.
Is this for an upgrade to Pro? I have both CDs, the PC came with home but I have not had the courage to do it. Home seems to work fine for most purposes including a small network.
If you do upgrade, let us all know how you get on!
To format a NTFS formated disk you can use a smale program: delpart, you can download it here:http://www.svrops.com/svrops/dwnldutil.htm, use a boot disk to start the pc and then use delpart, it wil clean the disk completely.