You dont even have to install another OS, that's my point - you can just run a LiveCD - it will even bypass all of your hard disks, so RAID or whatever won't make an ounce of difference. You can pull them out for all it cares! So no, you don't partition them first. Just burn a LiveCD (from a downloaded ISO), stick it in your PC, make sure the BIOS is set to read from CD first (rather than hard drive being first boot drive), and DONT INSTALL but just run it.