Chip credit cards don't need special holders to shield them

Q: There are many protective holders being sold for RFID (radio-frequency identification) credit cards. Is there some way to tell which of these wallets and card sleeves work the best?

Ed Krautsdorfer, Denham Springs, La.

A: There don't appear to be any independent ratings of RFID card holders, which claim to block radio waves to thwart potential electronic theft of card information.

The card holders became popular as RFID technology was introduced to credit and debit cards and U.S. passports over the past decade. They were designed to prevent a thief armed with special radio equipment from tapping a card's information from a few feet away.

But because credit and debit card technology has shifted from RFID to the more theft-resistant EMV (named after EuroPay, MasterCard and Visa), protective card holders aren't really needed. EMV cards are less vulnerable because their radio signal travels only a few inches. And EMV cards can only be used for fraud if a thief steals the card's information and recreates the card's ability to generate a one-time transaction code for each purchase, which would be difficult.

Q: When I downloaded software to a new laptop, I got a "1606" error message. I called a number I was given, and they claimed that I had the CSRSS and Koobface malware programs, and that they could help me for $249. But I don't trust them. How can I scan my PC and network to find out if this is a scam?

William Welch, New Brighton

What's the issue? The 1606 error message indicates there's a problem in the PC's registry, a database of settings. The presumption is that these registry problems were caused by CSRSS, a computer virus, and Koobface, a "worm" program that spreads itself through computer networks.

On the theory that this might be true, you can get rid of CSRSS and Koobface by running the free Malwarebytes program (tinyurl.com/nc7pfea) and Microsoft's free "Malicious Software Removal Tool" (tinyurl.com/oq66pxa).

Then you should repair the registry by downloading Microsoft's free automatic software fix at tinyurl.com/p7xya8z. The same website also explains how to fix the registry manually, but don't try that yourself. If you make a mistake in the registry, it can cause other PC problems.

Q: I tried your advice (tinyurl.com/jtys4k8) for changing the font size on my Google Chromebook, but it had no effect. What am I doing wrong?

John Novotny, St. Paul

The simplest way to enlarge the type or font size on the Chromebook is to simultaneously press the Ctrl key and the "+" (plus) key to zoom in, or the Ctrl key and the "-" (minus) key to zoom out. To return to the default setting, simultaneously press the Ctrl and "0" (zero) keys.