Q I'm interested in recycling a PC in a way that protects the information stored on the hard-disk drive, such as banking records, tax returns and Social Security numbers. For two PCs I recently recycled, I drilled some holes in the disks and cut a few pieces out of them. I know there is software to erase disks, but one of my PCs wouldn't even boot up. What's the best way to handle this?

MIKE GSCHLECHT, COON RAPIDS

A You're right to be concerned. A PC disk drive probably still contains all the data you ever stored on it, regardless of whether you deleted the information.

That's because deleting a file merely erases its "disk address" so the PC can't find it. The information is still there and can be retrieved with the proper software. (If you stored enough data to fill up your hard disk, the PC would eventually overwrite your old deleted data, but with today's high-capacity disks, that rarely happens.) Reformatting the disk is a little more effective, but the data can still be recovered.

People whose old PCs still run have the choice of downloading software that really does eliminate sensitive files from the disk. The free program Eraser works with operating systems from Windows 95 to Vista, and overwrites your disk with patterns of new information, effectively obliterating the original data. It can be downloaded from www.startribune.com/a4288.

But if a computer isn't running, physical destruction of the disk is a good solution. Drilling a hole in a disk will prevent nearly anyone from reading the data.

My solution has been to remove the sealed hard-disk modules and burn them (carefully, since the sealed metal containers might pop open).

How do you remove a disk drive? Open the PC case, disconnect a couple of wires and unscrew some brackets. To get a better idea of how this works, see the illustrations at www.startribune.com/a4289 (desktop PC) and www.startribune.com/a4296 (laptop).

Q What software can I buy to speed my computer back to, or close to, the speed it had when I first purchased it?

KALE DANBERG, BROOKLYN PARK

A There are programs that clean up your PC, enabling it to run a bit faster. Some of them can be found at www.startribune.com/a4292. A list of potential causes of PC slowdowns can be found at www.startribune.com/a4293.

Remember, some slowdown issues aren't easily fixed. An older PC running newer and more complex software may run slower, but the solution is to buy a new PC.

E-mail your technology questions to tech@startribune.com or write Tech Q&A, 425 Portland Av. S., Minneapolis, MN 55488-0002. Please include a full name, city and phone number.