Using 'Do Not Track'
Q. I have a new Windows 8 computer. How can I tell if my Internet Explorer is set to block Web sites that want to track me?
A. If you chose the express settings option when you set up your Windows 8 machine, Do Not Track is most likely enabled already; a visit to Microsoft's Do Not Track test page at bit.ly/16n3XCl is one quick way to check. You can also look at the browser's settings.
In Internet Explorer, click (or tap, if your computer has a touch screen) the gear-shaped Tools menu icon and choose Internet Options. In the Internet Options box, select the Advanced tab, scroll down the Settings list to the Security section and the "Always send Do Not Track header" option. If the checkbox is turned on, your browser is set to send Do Not Track requests to the sites you surf.
Not every site or content provider that collects browser information for analytics and advertising will honor requests to stop tracking your Web surfing.
You can find out more about Do Not Track at http://donottrack.us.
Internet Explorer 10, and some earlier versions, can also use Tracking Protection Lists to block third-party content from sites on that list. Microsoft has more information about Tracking Protection on its Web site at bit.ly/13F0oCt.
Mac OS X
Q. How do you reinstall the operating system on a Mac with no DVD drive or system installer discs?
A. One method is to use the Recovery partition Apple includes with its recent Mac computers and OS X system software (Lion and Mountain Lion editions).
The partition includes utilities and tools for reinstalling the operating system, repairing drives and restoring the Mac's contents from a Time Machine backup file. You can find the Recovery partition by restarting the Mac and holding down the Command and R keys as the computer boots up.
When the computer finishes its start-up routine, you should see an OS X Utilities window in the middle of the screen listing four options, including one for restoring the operating system. You need a broadband Internet connection to download the four-gigabyte OS X software to reinstall.
Apple has more information on OS X Recovery (and how to create a bootable external drive for recovery) at support.apple.com/kb/HT4718.
TIP OF THE WEEK Is the TV remote control always getting lost in the couch cushions? If you have a Samsung Galaxy S4, you can change channels with the smartphone's built-in infrared hardware and WatchON app ( samsung.com/watchon). The app works with many brands of TV sets and service providers, and includes a programming guide.
To use the Galaxy S4 as a remote, find and tap the WatchON icon and work through the setup screens that ask for your location, television service provider and TV brand; the app can also pair with set-top boxes and other home theater components. Once you have successfully paired the phone with your equipment, WatchON supplies a channel guide and a button to tap when you want to change the channel or adjust the volume. (Swipe up on the basic remote screen to see controls for components like digital video recorders.) In the WatchON app settings, you can have the remote control appear on the Notification and Lock screens.
With infrared hardware or Wi-Fi, other smartphones can work as remote controls with the right apps and TV hardware, like the LG TV Remote app for the company's newer Smart TV sets. Apple's own Remote app (free in the App Store) can also turn an iOS device into a controller for iTunes and the Apple TV box. 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.