partitioning your HD wont delete your stuff!
well, i've partitioned mine and it just partitioned it without deleting anything.. :]

Paragon partition manager|

use it with care tho!, it can get confusing... i deleted everything off my HD when I first started using it, then I had to reinstall everything..

anywayz, if you want to FORMAT your HD and if you want to make data non-recoverable then use
darik's boot and nuke:

it works just like a Shredder, Shredders only delete files and documents, this one formats any HD that it could find on the computer, data will be non-recoverable [read the documentation to get a better idea about how it workz and how to use it]... :]

hope tha helpd