02/06/2003

You may have heard warnings about protecting your private information when either selling or dumping your old computer. It could be as risky as throwing away your wallet with all your credit cards and personal ID inside. Is there a foolproof way to make sure that data disappears? We did some digging to find out.

You may have wanted to smash your computer at one time or another, but it may actually be a good idea if you're about to replace it with a bigger, better model.

"Your personal data is at risk when somebody resells a machine," says Mark McLaughlin of Computer Forensics International.

Just ask Todd Baitsholts. He has an old computer he wants to give to charity. First, he reformats the hard drive, and then he reinstalls Windows. “We hope to erase all the data and not have it accessible to anyone."

That should do it, right? To find out, Todd agrees to let computer expert Kevin Kranz take a look at the machine. Here's what he found.

"These are all the directories I was able to get information from." There are old invoices. Financial data. The list of recovered files takes up pages and pages.

"Well, a file is never really deleted until it's overwritten, and that's a very fundamental issue in computer forensics," says McLaughlin.

McLaughlin is sounding the alarm after he tested eight hard drives purchased at second-hand shops around the country. “We found some unbelievable things. Credit card numbers, social security numbers of celebrities, of Oscar-winning actors."

So, how can you protect your data? Reformatting doesn't do it.

“It makes the file inactive,” McLaughlin says, “but the file contents are still there."

And while erasing data magnetically helps scramble the files, even this method is not foolproof.

"What they should do first is they should wipe the drive," says McLaughlin.

You can buy software that scans the disc and bit by bit overwrites the old data -- in other words, replaces the important stuff with frivolous numbers. However, it takes anywhere from 3 to 20 passes. "And when you overwrite it so many times, it's unrecoverable," McLaughlin says.

The software costs about $40, but the best method for making that data disappear, according to McLaughlin, is both free and easy.

“What I recommend is taking the drive out of the machine and taking a drill and running a drill through it several times."

Use a drill, a hammer, whatever it takes to physically destroy the drive.

Police and computer forensics experts use software costing thousands of dollars to recover data.

But what's scary is that simpler software is available in computer stores, making it possible for just about anyone to be able to see deleted files hidden on the hard drive.

Web story produced by Jay Ditzer.