QWe received an e-mail from Comcast's Xfinity Internet service that said our PC may be infected with "bot" software, which we hadn't heard of before. But I can't tell that there's anything wrong.

Comcast is requesting that we let them use software to remove the bot that will cost us $360. Is there another way?

BOB BUSCH, EDEN PRAIRIE

ABot (as in robot) software takes over your computer and makes it follow instructions from some scam artist on the Internet.

For example, a PC that's been turned into a bot could run a phony phishing website that tricks other people into giving it valuable personal information. Or it might steal your online passwords as you type them, or use your PC to forward mountains of spam.

Because there are no outward signs that anything is wrong, literally hundreds of thousands of computers have been taken over without their owners' knowledge. (The recently discovered Flashback bot took over half a million Macintosh computers.) These groups of compromised computers, called "botnets," quietly carry on their illicit business.

Comcast probably spotted the bot software because there was a large amount of Internet traffic leaving your computer.

Without knowing which bot software is involved, it's hard to say whether it will be difficult to remove. But before I paid Comcast $360, I'd try the free Malwarebytes Anti-Malware program (find it at tinyurl.com/6my24hx and click "download now.") To avoid potential interference from the bot software, I suggest you download, install and run Malwarebytes on a flash drive.

QI have an HP Pavilion dv8 laptop that keeps losing its Wi-Fi connection. I usually have to reset the adapter on the PC, but that only lasts for a while. I've seen online that other people have had the same problem. What can I do?

ANTHONY WILLIAMS,

FORT LAUDERDALE, FLA.

AIt's probably a laptop electrical issue, which is not something the average person should try to fix.

Fortunately there's an inexpensive solution: turn off the PC's internal Wi-Fi and buy a Wi-Fi adapter that fits into your PC's USB port. Adapters cost as little as $14; see tinyurl.com/7r8w4wc or tinyurl.com/ybjeoam.

QI have photos clogging my Mac and PC. What software is best for getting rid of duplicate pictures?

JOANN ANGLE, LAKELAND, MINN.

AFor PC software that helps eliminate duplicate photos, see tinyurl.com/crsk3o8. For Mac software, see tinyurl.com/6udnazm or tinyurl.com/7bzpmpe.

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