Create a system Image using any of the fine Imaging apps (Acronis True Image Home or Macrium Reflect are 2 such apps) then open Disk Manager and format the partition. This will leave you with a ready made Data partition.
Imaging is a much better method to back up you entire system as it makes a "snapshop" of the entire system including Win 7, all installed apps, customizations, everything. You can restore the partition to it's exact condition in less than 10 minutes should disaster occur.