Q: My girls aren't able to connect to their grandparents' home Wi-Fi network with their iPhones. The girls enter the correct password, but never get connected. What can we do?

Joanna Esposto, Blandon, Pa.

A: When iPhones can't connect to Wi-Fi networks, the most likely source of the problem is the home network. As a first step, restart the Wi-Fi network by unplugging the Internet modem and the Wi-Fi router (in some cases, both functions are built into a single device). Wait a few minutes, then plug the modem in again. If the router is a separate unit, wait for the lights on the modem to illuminate before plugging in the router.

If that doesn't work, turn off the iPhones, then restart them. If that still doesn't solve the problem, trying turning the iPhones' Wi-Fi off and then on again.

If you still don't get any results, tap the name of the home network the iPhones are trying to connect to; this will take you to another screen where you should choose "Forget this network." Then select the home network again and try logging in.

If you're still not having any luck, check to see if your daughters have given their iPhones network names with apostrophes, such as "Carrie's iPhone." If so, delete any apostrophes (go to Settings, then General, and then About to find the "name" box). Try connecting again.

If that doesn't work, reset the router to its default settings (there's usually a button for that). But resetting means you'll have to re-create the network name and password.

Adios, XP

More questions about the end of Microsoft's Windows XP security updates on April 8, which will leave XP machines vulnerable to hackers:

Q: Jean Krocak of New Brighton and Jeff Golden of Annandale, Minn., asked if they can safely keep using "XP Mode" on their Windows 7 PCs. XP Mode allows them to use older, XP-compatible software that otherwise wouldn't work on Windows 7.

A: No, Windows XP and Windows 7 XP Mode are the same thing, and neither one will be safe after April 8. Microsoft recommends using XP Mode only when a Windows 7 PC is disconnected from the Internet. (A Windows XP PC would be safe only if never connected to the Internet.)

Q: I use Windows 7. But will I be vulnerable when I receive e-mails from friends who are still using Windows XP after April 8?

Nancy Mason, Jacksonville, Fla.

A: Windows 7 isn't affected by the security threat to Windows XP. But if a friend's XP PC were taken over by hackers, you might receive more spam e-mail. Compromised PCs are often used to relay spam, and the friend's PC would have your e-mail address.

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