Reader Steve wrote in with this question:
"I need to remove personal files from a company machine. What do you recommend to permanently shred such files?"
This is a common scenario. You might be returning a company laptop before leaving for another job, or just handing off an old machine prior to getting a newer one.
Heck, maybe the IT department just decreed that personal data is a no-no on company hardware.
Whatever the case, you want to be sure to remove all traces of your files. What you need is a file shredder, a utility that not only deletes selected data, but also makes it impossible to reconstruct. (It's akin to feeding sensitive paper documents into an actual shredder.)
There are countless file-shredding utilities out there, many of which offer a free trial that would probably take care of your one-time shredding needs.
For example, check out IT Works Software's AceErase File Shredder, which "overwrites all addressable locations" of each selected file.
The free version makes only one pass over each file, unlike the US$34.95 Pro version, which can make up to 99 passes. I suspect that one is enough for removing all traces of your personal data; you'd need more only if you were shredding actual company documents (legally, of course) to ensure maximum protection.
Needless to say, you'll want to make sure you've copied any important files to an external drive before starting the shredding process.