Wipe HD?

Is there a decent way to wipe the unused portion of a HD w/o affecting the utilized portions?

Would prefer no one goes and does easy snooping when I turn in a work laptop, doubt they will, so its not like I need level 10 reverse rewrites or something.

You can create a new partition with 100% of your free space allocated to it and then format the hell out of it

http://www.portablefreeware.com/?id=1470&ts=1233111891

^ thanks!

ccleaner can wipe free space