Q: I think I accidentally changed something in my Windows 7 PC's advanced settings, and now the PC's directory can't see my external hard drive. I can't restore my computer to an earlier date because it can't see the external hard drive on which I backed everything up. What should I do?

Pierre Girard, Golden Valley

A: First, let's eliminate hardware problems as a possible cause.

Try plugging your external drive into a different USB port on your PC. If the PC recognizes the drive, the USB port you were using isn't functioning. If nothing changes, try plugging the external drive into another PC.

If the other computer can't see the external drive either, you have a problem with the drive. Take it to a PC repair shop to see whether the data on it can be saved to a new external hard drive.

If the other computer recognizes the drive, the problem lies with your PC.

If so, try using "system restore" to return the PC's settings to a date before the appearance of this problem (see tinyurl.com/kxanto5). System restore won't affect any of the data stored on your PC, but it will fix any advanced settings you may have altered.

Why will this work when your PC can't see your external backup drive? System restore uses only prior computer settings data stored on your PC's hard drive; it doesn't need to access the external hard drive.

Q: I've discovered that I have the Zeus malware program on my PC. Is there a free or cheap method of getting rid of it?

Russell Steiner, Heath, Ohio

A: The Zeus malware is truly harmful. But 10 years after its first appearance, it is well-understood and can be removed by the average PC user.

However, removing it is a laborious process that uses the free versions of four different anti-malware programs (see tinyurl.com/k44vz8a).

The Zeus malware has spread misery since it was discovered in 2007. Besides stealing passwords and online banking information, it acts as a conduit for downloading additional malicious software. As a result, it has been used to install ransomware (in which PC data is encrypted and a ransom is demanded to free it), and to show pop-up windows that falsely claim a PC has a virus infection and offer to fix it for a price (see tinyurl.com/y8bbqpfv).

Q: We wanted to put photos on Craigslist using my Kodak Easyshare camera and its PC software. But the photos wouldn't transfer to Craigslist. Instead the photos were circled in red, with a red line through them. What's wrong?

Orren Bradley Jr., Sahuarita, Ariz.

A: I suspect that the Kodak Easyshare software, which hasn't been available since 2013, isn't compatible with the Craigslist website.

A better alternative is to remove the memory card from your Easyshare camera and insert it into a memory card reader (either one built into a PC or an external one that plugs into a USB port.)

Your PC will read the camera card as it would a flash drive. Copy the pictures from the card to a new folder on your PC, then upload them to Craigslist.

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