I have replaced a dying hard drive in XP and want to use the old drive as a scratch disk for non-critical things. The old drive still has the full XP install (although it won't boot). What's the best way to wipe it out so I can use it as a secondary internal drive? I understand that there can only be one active partition. Does this mean per disk or per PC? If I were to just put the old drive in on the 2nd sata channel without changing it in any way, would it muck things up?