Q: Occasionally I get a pop-up message on my four-year-old PC that says "To check for new device software, connect your PC to the internet and press 'continue.' " There is no company logo on the message and I'm leery of it, so I've been pressing "cancel," which makes it close until another day. I have looked in Windows Task Manager, but I can't find the program there. I run McAfee security software without finding anything. Also, over the past several weeks, my PC has had bouts of agonizingly slow internet performance. It usually goes back to normal after I run Windows Disk Cleanup, run a security scan and reboot. What's wrong?

Warren Weise, Lakeville, Minn.

A: You were right not to click "continue." The rule of thumb for computer users is: Never click on something unless you know what it is.

In this case, we discovered what caused the upgrade message by e-mailing back and forth a few times. The behavior of the odd message matched that of the "software upgrade assistant" program that Verizon Wireless provides for users of Samsung smartphones. You confirmed that your wife had a Verizon Samsung phone.

When you clicked on a taskbar command to show "hidden icons," the program producing the message was revealed to be "VZW Software Upgrade Assistant-Samsung." My guess is that the program was installed on your PC as part of the phone's setup. The "upgrade assistant" provides an alternative to downloading software updates directly to the phone; the updates can instead be downloaded to the PC and transferred to the phone via USB cable.

There are many possible causes of a slow computer, including malicious software, hard disk congestion or internet connection issues.

Download and run the free version of the Malwarebytes security program (see tinyurl.com/jsdacdk and click "free download.")

See my recommendations in last week's column for fixing hard drive congestion and determining the speed of your internet connection (see tinyurl.com/gpt525l).

If you have upgraded to Windows 10, check your PC manufacturer's website to see whether your four-year-old PC is on the list of models that can handle the upgrade. If your PC isn't on the list, you may need to reinstall the previous version of Windows.

Q: We have been using Sony wireless headphones with our living room TV for several years, and recently purchased a second set for the bedroom TV. But, when both are in use, they interfere with each other — the bedroom headphones pick up the living room TV signal and vice versa. I assume this is caused by the short distance between the two rooms. What can we do?

Bill Trevis, Brainerd, Minn.

A: Your headphones receive a radio signal from a transmitter that is connected to the TV. If you can move the transmitter and headphones closer to each other, you might strengthen the signal enough to avoid interference. You may also switch one of the transmitter-headphone pairs to a different radio frequency, or channel. Move to a new channel by using the selector switch on the transmitter, then match the headphones to the new frequency using their tuning selector or tuning button.

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