Q: I'm on a low-usage monthly phone plan. As a result, I'd love to be able to set most of my smartphone apps to use only free Wi-Fi internet connections, and to allow only a few apps to access my cellular connection. But I can't find any way to do it on my Samsung Galaxy S5 phone. Is there an app that will let me control Wi-Fi and cellular connections for my other apps?

John Williamsson, Manning, S.C.

A: There is such an app. What's interesting is why there needs to be one.

This is a case of an operating system manufacturer deciding how much control to give phone users. Within the Google Android operating system used by your Galaxy S5 phone, there is no way to "turn off" an individual app's ability to use the cellular network and force it to rely on Wi-Fi connections instead. Apple made the opposite decision with its iOS operating system; iPhone users can control an app's cellular or Wi-Fi use.

It's worth noting that Android does offer users some less-specific controls over a phone app's cellular data use, such as limiting total cellular data consumption in a month, or preventing apps from updating themselves when not in use. For details, see tinyurl.com/gusolrt.

And in some cases, Android app makers will let you restrict their app to Wi-Fi only, or at least reduce its cellular data consumption. The Netflix app allows you to restrict video streaming to Wi-Fi only, and the YouTube video app and the Pandora music app let you minimize their use of cellular data, although you can't turn it off. (See "Keep streaming video and music apps from gobbling too much data" at tinyurl.com/j363fx7).

But to get the same functionality as iPhone users, you need an Android app called NetGuard. It will enable you to decide which of your phone's individual apps can use only cellular or only Wi-Fi connections. While NetGuard is free to download from the Google Play store (see tinyurl.com/pn7qauw for details), users must then pay to use its various controls.

Q: As a substitute teacher, I need to access an education website that deals with "absence management." I can reach this website with my tablet and laptop computers, but not with my desktop PC, which gets a "forbidden" notification. I've tried emptying the browser's cache memory, typing the website address instead of using a bookmark and switching browsers, but nothing helps. What can I do?

Laurie Hauge, Minneapolis

A: Some legitimate software on your desktop PC is probably interfering with Windows, and generating the "Access Denied/Forbidden" error.

This is usually caused by advertising removal programs, security software, antivirus software, Web accelerators (software that connects to a special internet server to download data faster) or download assistants. If you have any of these programs, try turning them off to see whether the "forbidden" error disappears. If there's no way to turn off a program, uninstall it.

If that doesn't work, the problem could be caused by a Windows file called "hosts," which maintains a list of major internet servers. Fixing the hosts file involves copying some data from a Microsoft website to your desktop PC (see tinyurl.com/hpl7w9x).

E-mail tech questions to steve.j.alexander@gmail.com. Include name, city and telephone number.