Q: I've been blocked from signing into the Gmail account that I've had for years. There doesn't seem to be any way to get help from Google, aside from the online instructions that don't work for me. (I previously gave Google the backup e-mail address and phone number that are supposed to help regain access to an account, but using them hasn't helped.) What can I do?

Larry Struck, Edina

A: It's possible that your Gmail account has been hacked, and the recovery information associated with it — your phone number and backup e-mail address — have been changed. That would explain why you haven't been able to access the account.

To regain control of a hacked Gmail account, see tinyurl.com/yboffdbe or call Google's customer support number, 650-253-0000. (For other useful Google contact information, see tinyurl.com/ycoanlgt). For safety, try using "two-step verification" for your Gmail account. In addition to using a password, you would be required to enter an access code that is sent to your cellphone via text, voice call or a Google phone app (see tinyurl.com/mfrbjcl).

Q: I've been receiving e-mails from addresses that consist of a series of letters and numbers, followed by the "@" symbol and a name that ends in "onmicrosoft.com." Are these harmful e-mails? I always move them to the spam folder, but is there a way to block them completely?

Sharon Grube, St. Marys, Ga.

A: The messages are fake and potentially harmful. Spammers (people who send junk e-mail) often use e-mail addresses that have misspellings or extra letters attached to a familiar name, such as Microsoft.

While you can't block all spam, each time you send an e-mail to the spam folder you help your account's "spam filter" "learn" what kind of mail you consider to be junk. In the long run, that will mean fewer e-mails of that type will reach your inbox.

In addition, your e-mail provider, TDS Telecom, allows you to increase the sensitivity of your spam filter (see tinyurl.com/y8gtopp8) so it will stop more junk e-mail. But the more sensitive the filter is, the more likely it is to classify some legitimate e-mail as spam, so check the spam folder regularly to rescue the "good" e-mail.

Q: I recently got a pop-up message, apparently from Microsoft, that my PC had been compromised. It gave me a number to call before trying to use the PC again. I called, and the technician said my PC had been hacked, but that they could fix the problem and install security software if he took control of my PC. I let him take control, and paid $300. Was I scammed?

Jim Morton, Hopkins

A: Yes, this is a common scam. Microsoft won't contact you via pop-up, or give you a number to call. But there's additional risk because you've relinquished control of your PC to a stranger, who may have stolen credit card numbers or passwords stored there, or left behind malware. If your PC contained card or password information, be on the alert for fraudulent credit card charges, and change the passwords. Also, run the free version of the Malwarebytes security program (see tinyurl.com/j32jr94) to find any harmful software on the PC.

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