Journal JakartaDean's Journal: Erase disk / partition table
In linux just use dd to write 512 zeros to
dd bs=1 count=512 if=/dev/zero of=/dev/hda
That will wipe the boot block clean, then you can use it like a brand new drive.
Or if you want, just zero out the partition table using a seek=446 and a count=64 instead of the count=512
Thanks PalmKiller