Q: I coordinate the St. Paul Classic, a large bike tour, and we are deciding how to back up our mailing list of 42,000 names and addresses. We now save this information in cloud storage and on a couple of archival CD disks, and it's been suggested we also make a printout. What's the best way to safely store this vital information?

Richard Arey, St. Paul

A: Using cloud storage is fine, but I would never depend on it exclusively because cloud providers can be hacked, lose files or go out of business. In addition to the cloud, you should back up the information locally in two ways, on an external hard drive and on a CD disk or flash drive. These local backups should be kept at different locations in case of fire, theft or other disaster. You should update the backups as often as the list undergoes significant changes.

In addition, remember that technology for storing data is constantly changing, which can create compatibility issues. New computers may switch data storage formats, storage media capacities or storage speeds (for example, USB 2.0 vs. the faster USB 3.0). At some point, older storage technology is no longer supported (for example, the floppy disk), so keep up to date.

Printouts are a valuable emergency backup, but retyping 42,000 entries from a printed document isn't practical. You'd need an "optical character recognition" scanner and software.

Q: You suggested using Windows Disk Check to test for disk drive problems (see tinyurl.com/pjr4kz5). But when I restart my Windows 7 PC, the Disk Check program is canceled before it can start. What's wrong?

Jack Botterbusch, Jacksonville, Fla.

A: Disk Check may be prevented from running because of a setting in the PC's Registry, a database of Windows operating rules. You can modify the Registry settings to correct this. Go to Start and type "regedit" in the search box. Be careful because making a mistake in the Registry can cause other PC problems. Another possibility is that the "autochk.exe" file that runs Disk Check is corrupted. For details on fixing both problems, see tinyurl.com/kue2hdg.

Q: I have several old desktop computers that I'd like to dispose of, but first I'd like to wipe the hard drives clean. Is there an easy way to do that?

George Gaffer, Tucson, Ariz.

A: Yes, there are many "data destruction" programs that will permanently erase a hard drive, and you can find a list of free ones at tinyurl.com/7zsjtbm. The destruction process is important because data the computer has "deleted" actually remains hidden on the hard disk until later overwritten by new information. That hidden data can be viewed by anyone using a file recovery program. Destruction programs overwrite all hard drive data, making it unrecoverable.

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