QI recently signed up for mobile broadband service from Verizon Wireless, which I use on my laptop computer. How secure is this type of service for doing online banking?

TONY MIDILI, Tucson, Ariz.

AToday, you don't have much to worry about, but in the future you might.

Cell phone networks have been relatively safe from hackers until now because they operated on their own, isolated from Internet threats. Despite some recent laboratory evidence that the GSM (Global System for Mobile Communications) networks used by T-Mobile and AT&T might be vulnerable to hackers, experts doubt that such an attack could work in the real world. They say cell signals are too elusive for hackers because they hop between cell towers.

But the increasing popularity of smart phones creates another type of cellular threat: smart phone apps. Unlike your PC, which uses a Web browser for online banking, smart phones typically rely on banking apps, tiny programs that connect a smart phone directly to a bank.

But security vulnerabilities recently were discovered in banking apps for the Apple iPhone and for smart phones using Google's Android operating system. Banking data stored on a phone could be found if the phone were stolen or if the owner could be tricked into visiting a malicious website. See details at tinyurl.com/2g2gdbj.

Cellular users may face other threats in the future. Cellular networks might become more vulnerable as they build 4G, or fourth-generation, networks. Most 4G networks use the Internet Protocol technologies that hackers understand. And, as more people access the Internet via cell phones, more malicious hackers are likely to follow.

QI've set my Windows XP PC monitor to go into power-saving mode 10 minutes after becoming idle. But after I use Facebook, the monitor won't go into power-saving mode until I re-apply my settings, which haven't changed. What's wrong?

ED ROUEN, MINNEAPOLIS

AI'm not aware that using Facebook can affect the power management settings for your monitor. However, any mouse or keyboard activity will awaken your monitor from power-saving sleep mode, in which the screen goes dark. In the case of a mouse, all it takes is a tiny vibration to wake up your screen.

In addition, some screen savers can interfere with sleep mode. To turn off your screen saver, right-click your screen and choose "Properties." In the resulting menu, click the screen-saver tab and, in the pull-down screen-saver menu, choose "None." Click OK.

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