You've gotta love a program that's as small, simple, easy to use, and straightforward as Roadkil's DiskWipe. Download it, unzip it, run it, and use it to overwrite the data on your disks. The program lets you select a drive--including removable drives--and write the entire drive with zeros or random numbers. You may also run multiple passes if you're really paranoid.

You could pay for more impressively-styled software, but there's no reason. The program worked for me, it most likely will for you as well. By the way, if you find it handy, Roadkil will accept donations at the Web site (though the donate button in the About dialog did not work for me).

--Jon L. Jacobi