The clash between browsers and security

Q: My Firefox web browser has trouble connecting to secure websites such as Amazon and Netflix. I get the error message "SEC_ERROR_UNKNOWN_ISSUER," and a pop-up box claims that these websites aren't secure, or that I need new website certificates. I've reinstalled Firefox several times, but that hasn't solved the problem. What can I do?

Gene Schwope, Woodbury

A: The problem may be caused by a conflict between Firefox and your security software, or by malicious software on your PC.

Software conflict: Secure websites, such as those that handle financial transactions, provide Firefox with digital "certificates," issued by a third party, that guarantee the sites are legitimate. (See my previous column on website certificates at tinyurl.com/hl5hd9p).

But some PC antivirus software, including Avast, Bitdefender, BullGuard, ESET and Kaspersky, can interfere with Firefox receiving a website's certificate, triggering the error message you received. If you use one of these programs, change its settings (see tinyurl.com/zbgeruv).

Malware: Odd PC behavior can occur if your computer picks up malicious software from a website or e-mail. Run the free Malwarebytes security program (see tinyurl.com/jsdacdk).

Q: I just bought a new Lenovo laptop with Windows 10. But the search box repeatedly appears on the screen, slowing down my work. Is there a way to shut it off?

A: The search box in Windows 10 is quite intrusive, thanks to the operating system's Cortana digital assistant. But you can turn off the parts of Cortana that easily initiate searches.

If you use the laptop's touch pad, you may be accidentally starting the search box with a finger tapping gesture that Cortana interprets as a request to open. Turn off the touchpad's ability to recognize those movements.

You can also turn off Cortana's ability to respond to voice commands. Cortana may activate the search box because it mistakenly thinks you used the trigger words "Hey, Cortana."

Also turn off the feature "Taskbar Tidbits" that allows Cortana to interrupt you with tips using the search box. To switch off all these aspects of Cortana, see tinyurl.com/j6px22l.

Q: I usually leave my 2-year-old HP laptop on and let it go to "sleep," but now it won't wake up. When I close the lid and reopen it, the power light comes on and the screen is blue, then they both go off. I tried doing HP's suggested "hard reset" that involves removing the battery, but it didn't fix anything. Can the PC be fixed, or is it time to recreate all of my personal information?

A: Ask a repair shop to determine what failed. Components such as a screen or a hard drive can be replaced, although the cost may cause you to buy a new PC instead. If the hard drive is OK, its data can be transferred to the hard drive in a new PC. If the hard drive failed, and you haven't backed up your data, you will have to recreate your personal information.