Q. How do I turn off the Amber Alerts on my phone? Can I turn off other government messages as well?
A. Amber Alerts, one of which recently awakened many New Yorkers in the wee hours, are urgent bulletins about abductions and are issued by the National Center for Missing and Exploited Children along with public safety officials. These free alerts, along with text messages about extreme weather, threatening situations and presidential announcements of national emergencies, are part of the Wireless Emergency Alerts system (www.fema.gov/wireless-emergency-alerts) that began to operate fully last year.
The Federal Emergency Management Agency says people can opt out of Amber Alerts and alerts for "imminent threats" like serious weather. Alerts issued by the president, however, cannot be turned off, as mandated by Congress.
To turn off the alerts on an iPhone, tap open the Settings icon, tap Notifications and flick down the screen to Government Alerts, where Amber and Emergency alerts can be turned off or on. For Samsung's new Galaxy S4, open the Messaging app, press the Menu button and then Settings. From there, tap Emergency Alerts to get to the screen where you can turn off Amber and weather notifications.
The steps for turning off alerts on other Android phones vary by system version and wireless company, so check with the carrier for specific instructions. Other types of phones that receive Amber Alerts can unsubscribe by addressing a text message to the short code 26237 with the keyword CANCEL in the message body; sending END, QUIT, STOP or UNSUBSCRIBE should work, too.
The Amber Alerts and emergency warnings are intended to help save lives, so consider all the factors before turning them off either temporarily or permanently. The Federal Communications Commission also has information about the Wireless Emergency Alerts system at www.fcc.gov/guides/wireless-emergency-alerts-wea.
An Amazon Kindle
Q. I want to buy a Kindle Fire tablet, but I'm worried that right when I do, Amazon will announce new models and I'll be stuck with the old one. If that happens, can I return the outdated version?
A. People can receive a full refund for a Kindle bought on Amazon.com if the device is returned within 30 days of delivery, as long as the device is still in new condition and in its original packaging. Kindles received as gifts can also be exchanged within the 30-day period.
Details about returning a Kindle (or other items) are on Amazon.com. Just click the Help link at the top of the page and then click Returns & Refunds in the Topics list.
People who bought a Kindle from a third-party retailer (and not from Amazon directly) should check with that store on its return and refund policies.
TIP OF THE WEEK The Web has many music services to keep your speakers humming, but if you have the time and attention, you can easily call up a whole playlist of videos from your favorite artists. Just visit the YouTube Music Discovery Project page at www.youtube.com/disco, type in the name of a band or artist, and hit the Disco button. YouTube then searches its vast archives for matching clips and creates a video playlist.
The resulting playlist can include a variety of material, including official artist videos, digitized television clips, karaoke tracks and more. Audio quality varies and commercials may interrupt, but the Music Discovery Project search can haul in a few hidden gems or some obscure concert film. J. D. BIERSDORFER
Personal Tech invites questions about computer-based technology to QandA@nytimes.com. This column will answer questions of general interest, but letters cannot be answered individually.
This article originally appeared in The New York Times.